Pharmaceutical Inorganic Chemistry

Radioactivity

The phenomenon of spontaneous emission of certain kind of invisible radiation by certain substance is called Radioactivity. The substances which emit such radiation is called

Radioactive substance. It was discovered accidentally by the French Scientist Henry Becquerel.

Radiopharmaceuticals are used in medicines. It is used to treat cancerous tumors, to diagnose thyroid disorders and other metabolic disorders including brain function.

Radioactive Rays

Radioactive radiations are composed of three important rays α, β and δ which differ very much in their nature and properties.

α-rays

These rays or particles are positively charged. It consists of two unit positive charge and has a mass which is nearly four times that of hydrogen atom. These are heavy, slow moving and their penetrtion power is slow. These rays ionise the gas through which they pass.

During the emission of a-particle from a radioactive element, atomic number decreases by 2 unit and mass number decrease by 4 units.

β-rays

These rays or particles are negatively charged. They have negligible mass. These having smaller mass, higher speed and thus β-particles are much more penetrting than aparticle. They have lower ionising power than α-rays.

During the emission of β-particle from a radioactive element, atomic number increases  by 1 unit and there is no change in mass number.
For example :

γ-rays :

These rays are neutral i.e. do not carrying charge. The particle of these rays has negligible mass. As they do not have any mass, their ionising power is also very poor. They not affected by magnetic field and are having the speed of light.

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Isotopes

Atoms of an element which have the same atomic number but have different mass number are called Isotopes, in other words, isotopes are atoms of the same element whose nuclei contain the same number of protons but different number of neutrons.

When the radioactive isotopes undergo nuclear reactions and they produce α, β and γ particles. The original nuclide is called the parent and the product is termed as daughter nuclide.

This phenomenon of nuclear changes is termed as disintegration or radioactive decay.

Radioactive Decay

According to the law of Radioactive Decay, the quantity of a radioelement which disappears in unit time (rate of disintegration) is directly proportional to the amount present. It is independent of temperature, so its energy of activation is zero.

Various forms of equation for radioactive decay are

Where λ, is a constant, and is known as decay or disintegration constant. Integrating the equation i)

C is the constant of integration and log N stands for logeN. Since the number of atoms of the radioactive substance present initially i.e. t = 0 is N₀

Substituting the value of integration constant

Converting log to the base e to the base 10, we get :

N_t= Nvunber of atoms that nucleid present after time t.

N₀ = Initial number of atoms of the nucleid at time 0.

λ = Decay constant

This equation is similar to that of the first order reaction, hence it is seen that radioactive disintegration are example of first order reactions.

Units Of Radioactivity

Units of Radioactivity is Curie. Its symbol is Ci or C. It refers to the activity of one gram of radioactive material and is equal to 3.7 x10¹⁰ disintegration per second (dps).

1 Curie = 3.7 x 10¹⁰ dps

The millicurie and micro curie are equal to 10^-3 or 10^-6 respectively.

1 Millicurie = 3.7 x 10⁷ dps
1 Microcurie = 3.7 x 10⁴ dps

But nowadays, the unit curie is replaced by Rutherford (Rd).

Rutherford (Rd) is defined as the amount of a radioactive substance which undergoes 10⁶dps.

Roentagen (R). it is the unit of exposure, 1R = 2.58 x 10^-4CKg^-1 (C = A Coluomb)

RAD: It is the unit of absorbed dose, 1 rad = 10^-2JKg^-1

However in SI system,

Bacquerel (Bq) : it is defined as one disintegration per second.

1 Bq = 1 disintegration per second

10⁶Bq=1 rd

3.7×10¹⁰ Bq=1c

Half-Life Of Radioelement

The half-life period is defined as the time required for a radioactive isotope to decay to one half of its initial value. It is denoted by t1/2

Where λ is disintegration constant. Each radioactive isotope has its own characteristic of half-life. Shorter the half-life period of an element, greater is the number of disintegrating atoms and hence greater is its radioactivity.

The half-life periods or half lives of different radioelements vary widely ranging from fraction of seconds to millions of years.

Half-lives for various radionucleides vary considerably e.g. Polonium- 122 has half-life of 3 x10^-7 seconds, uranium 238 has 4.5 x10⁴ years.

Average Half-Life Period

The reciprocal of the radioactive constant or decay constant is called average half life period. It is denoted by Τ (tau).

Example 1: Calculate the half-life period of an isotope if its disintegration constant is 1.237 x 10^-4 year^-1.

Solution.

Example 2: The half-life period of a radioactive element is 2.5 days? What is the value of decay constant (λ,) in mm^-1?

Example 3: A radioactive substance decay at such a rate that after 46 days only 0.25 of its original amount is left. Calculate the disintegration constant and half-life period?

Measurement Of Radioactivity

To measure the radiations ofalpha, beta and gamma rays many techniques involving detection and counting of individual particles or photons have been available. It include Ionisation Chamber, Proportional counter, Geiger-Muller counter.

Ionisation chamber: An ionisation chamber consists of chamber filled with gas and fitted with two electrodes kept at different electrical potentials and a measuring device to indicate the flow of electric current.

The fill gas can be Ar, He, air etc. These available in various size and shapes. They have poor resolution due to large number of charge carriers. They are operated in current mode.

Proportional counter: If the electric field gradient between the anode & cathode is increased by increasing the applied voltage, the electrons produced in the primary ionisation further ionise the gas molecule e.g. the number of ion pair is multiplied.

For each primary electron liberated, ‘ a large number of additional electrons are liberated, the current pulse through electrical current is greatly amplified.

In a certain original number of ion pairs. Proportional counters operate in this voltage region. They are usually operated in pulse mode and are used in the form of gas filled or gas flow counters for a, b and fission frequent counting.

The most common file pass is “P-10” consisting of 90% Ar and 10% methane. The energy resolution of the proportional counter is in the range of 5-10%.

Geiger-Muller Counter: It is one of the oldest radiation detector types in existence, having been introduced by Geiger and Muller in 1928. It is referred to as G-M counter or simply tube.

The simplicity, low cost and of ease of operation of these detectors have lead to their continued use to the present time. They can detect a, P and y radiations. It consists of a cylinder made up of stainless steel or glass coated with silver on the inner side which acts as cathode.

Coaxially inside the tube a mounted fine were works as an anode. It is having the mixture of ionising gas which contain a small proportion quenching vapour.

The function of quenching vapour are i) to prevent the false pulse, ii) to absorb the photons emitted by excited atoms and molecule returning to their ground state.

Chlorine, bromine, ethyl alcohol and ethyl formate are commonly used qenching agents. Radiation when enters the tube through a thin section of outer wall causes ionisation of atoms of the gas.

When a high voltage is maintained between two electrodes, the electrons and charged ions are attracted by the anode and cathode respectively. Each particle of radiation produces a brief flow or pulse of current which can be recorded by a scalar.

Scintillation Detectors

Scintillation detectors rely on theatomic ormolecular excitation produced. Deexcitation then results in the emission of light, a process known as fluorescence.

This light then act as a detectable signal. It consists of a cell, a photomultiplier tube coupled with phosphar or flour to convert scintillations into electrical pulses, an amplifier and a scalar.

Both inorganic and organic scintillations can be used as detector. There are two main types of scintillator :

Inorganic, such as Sodium Iodide: Single crystals of Nal, doped with an activator such as Thallium to modify the energy levels which are used to form detectors.

They are insulators and have a wide gap between the valence band and conduction band suitable activators are used to create excited states which decay by emission of light in the visible range. Other scintillation like CsI (TI), CsI(Na), Hi I (Er), BaF₂.

Organic Scintillator: It is used for simple α and β counting with 100% efficacy. Anthrene have high scintillation efficacy and stilbene low scintillation efficacy.
It suffer from the limitation of poor energy resolution.

Major Uses Of Radioisotopes

Storage, Handling And Precautions Of Radioactive Material

A care should be taken to protect people and personal from harmful radiation during handling and storage of radioactive material emits.

The following precautions are taken while working with radiodetectors, radio assays, traces experiments, manufacturing or handling of radioactive materials.

1. These materials should be handled with forceps or sutiable instruments and direct contact should be avoided.
2. Any substance which is taken internally (foods, drinks, smokes etc.) should not be carried in laboratory where radioactive materials are used.
3. Sufficient protective clothing or shielding must be used while handling the materials.
4. Radioactive materials should be kept in suitable labelled containers shield by lead bricks and preferably in remote corner.
5. Areas where radioactive materials are used or stored should be monitored constantly (tested regulary for radioactivity).
6. The final disposed of radioactive material should be done with great care to animals and environment.

Radioopque Contrast Media

Radioopaque contrast media are the chemical compounds having the capacity to absorb and block the passage of x-rays. So they are opaque to x-ray examination.

They are used as a diagnostic aid in radiology which emits x-rays. They can pass through soft tissues of the body but are observed at hard tissues (bone).

The ray produces a black spot on photographic plate by forming complex with silver bromide.

These rays does not form a bright spot of the similar shape as that of x-ray observing object is formed.

X-rays are electromagnetic radiations of short wavelength and have high penetrating power.

Radioopaque agents are typically iodine or barium compounds and are used for x-ray examinations of the kidney, liver, blood vessels, heart and brain.

Although they do not have the highest atomic numbers/they are the most easily incoorporated into molecules exhibiting low toxicity. They become concentrated in the organ to be studied.

Radiopharmaceuticals

Various radioopaque contrast media are used in the x-ray examination of gastro intestinal tract, gall bladder and bile duct, kidney and uretar, fallopian tubes, liver, blood vessels heart and brainets.

Barium Sulphate

Formula: BaSO₄

Mol. Wt: 233.4

Preparation

In nature it is found as barite; also as heavy spar.

It may be prepared by adding any soluble sulphate to a soluble barium salt. For example addition of sodium sulphate to a solution of barium chloride precipitates barium sulphate.

Barium chloride on treatment with sulphuric acid causes precipitation of Barium sulphate.

Physical Properties

It is fine, heavy, white, odourless, tasteless, bulky powder free from gritty particles. It is practically insoluble in water, in organic solvents and in dilute solutions of acid and alkalies.

The bulky is free from gritty particles. It does not have any toxic effects to man and the environment.

Chemical Properties

Barium sulphate on treatment with cone, sulphuric acid results in the formation of bisulphate salt.

Uses

1. It is used as a radiopaque contrast media for the x-ray examination of the git tract.
2. Barium ion stimulates smooth muscles causing vomiting, severe cramps, diarrhoea and haemorrhage.
3. It is used primarily as a whitening agent and as an insoluble support in industrial applications.

Radiopharmaceuticals Short Answer Questions

Question. 1. Define Radioactivity.
Answer. The spontaneous emission of certain radiations like α, β and γ-rays is known as radioactivity.

Question.2. t1/2 of radioactive element is 100 seconds? What is the value of its disintegration constant? •

Answer:

Question.3. In the sequence A→B→C→D. What is relationship between A and D?
Anwer: They are isotopes

Question.4. What is meant by rate of radioactive decay? Give general formula of decay constant?
Answer.

Rate at which radioactive element disintegrate is called rate of radioactive decay.

Where N₀ is initial amount of radioactive substance.
N_t is final amount of radioactive substance.

Question.5. Differentiate between a, P and y rays?
Answer:

Question.6. Define Curie?
Answer. It refers to the activity of one gram of radioactive material and is equal to 3.7×10¹⁰ disintegration per second. Its unit of radioactivity.
1 Curie = 3.7xl0¹⁰ dps

Question.7. Define Half life? How is it denoted?
Answer. Half life period is defined as the time required for a radioactive isotope to decay to one half of its initial value.
It is denoted by t1/2.

t1/2=0.693/λ

Where λ is disintegration constant.

Question.8. Give two examples of radioisotopes?
Answer.

1. Calcium 47
2. Cesium 137
3. Chromium 51
4. Iodine 123

Question.9. What do you understand by the term Radioopaque contrast media?
Answer. Radioopaque contrast media are the chemical compounds which are having the capacity to absorb or block the passage of X-rays.

Question.10. Give two examples of Radioopaque agents?
Answer. Barium sulphate And Iodine

Question. 11 What are the uses of Radioopaque contrast media?
Answer Radioopaque contrast media are used in the x-ray examination of g.i. tract, gall bladder, bile duct, kidney and fallopian tubes.

Question.12. How is Barium sulphate prepared?
Answer. Barium sulphate can be prepared by adding any soluble sulphate to a soluble barium salt.

For example:- Addition of sodium sulphate to a solution of BaCl2 precipitates barium sulphate.

Radiopharmaceuticals Fill In The Blanks

1. Radioactivity undergo …………………..reaction.

Answer: Spontaneous

2. An alpha particle carries…………….

Answer: 2 unit positive charge

3. An beta particle is……………… charged.

Answer: Negatively

4. Isotopes have the same ………..but different……………….

Answer: Atomic number, mass number

5. The order of reaction of radioactive decay is …………………

Answer: First order

6. The t l/2 of a radioactive substance is 100 second, its X is……………………

Answer: 6.93 x lO-sec-1

7. …………………… is used for the measurement of radioactivity.

Answer: Geiger-Muller counter

8. …………………..is gas filled detector.

Answer: Ionisation chamber, proportional counter

9. The time required by given amount of the element to decay to one half of its initial value is known as…………….

Answer: Half-life

10. P-10 gas is a mixture of…………..and………….

Answer: 90% Argon & 10% methane

Radiopharmaceuticals True Or False Statement

1. Radioactive decay is first-order reaction.

Answer: True

2. Alpha particles are identical with helium nuclei.

Answer: True

3. Rate of disintegration is inversely proportional to the amount present.

Answer: False

4. (5-rays have highest penetrating power as compared to a, y rays.

Answer: False

5. Radioactivity is a spontaneous process.

Answer: True

6. Geiger-Muller counter cannot detect a, (5 and y-radiations.

Answer: False

7. Radioopaque contrast media do not need any x-ray examination.

Answer: False

Radiopharmaceuticals Multiple Choice Questions

1. Radioactivity was discovered firstly by>

1. Henry Becquerel
2. Rutherford
3. J.J. Thomson
4. Madame Curie

Answer: Henry Becquerel

2. The unit of radioactivity is:-

1. Curie
2. Rutherford
3. Ohms
4. Both a) and b)

Answer: Curie, Rutherford

3. A device used for the measurement of radioactivitv is a

1. Mass spectrophotometer
2. Cyclotron
3. Nuclear reactor
4. G.M. Counter

Answer: G.M. Counter

4. Radioactivity is due to

1. Stable electronic configuration
2. Unstable electronic configuration
3. Stable nucleus
4. Unstable nucleus

Answer: Unstable nucleus

5. When a radioactive nucleus emits an a particle, the mass number of the atom

1. Increases and its atomic number decrease
2. Decrease and its atomic number decrease
3. Decrease and its atomic number increase
4. Remain the same

Answer: Decrease and its atomic number decrease

6. Which isotope on bombardment with a-partide mil have 17/8 O and 1/1H?

Answer: b)

7. The decay of a radioactive element follows first order kinetics. As a result of:-

1. The half life period= a constant k where k is the decay constant
2. The rate of decay is independent of temperature
3. The rate can be altered by changing chemical conditions
4. None of the above

Answer: The rate of decay is independent of temperature

8. Which of the following is correct?

1. Radioactivity is a statistical process
2. Radioactivity is a spontaneous process
3. Radioactivity is characteristics of some elements
4. Both b) and c) are true

Answer: Both b) and c) are true

9. Radioactive decay is a reaction of

1. First order
2. Second order
3. Third order
4. Zero-order

Answer: First order

10. a-rays have

1. +ve charge
2. -ve charge
3. no charge
4. Sometimes +ve and sometimes -ve

Answer: +ve charge

11. Gamma rays have

1. High penetrating power than a and P
2. No penetrating power
3. Less penetrating power than a and (3
4. None of the above

Answer: High penetrating power than a and P

12. Alpha rav consists of a stream of

1. H⁺
2. He²⁺
3. Only electrons
4. Only neutrons

Answer: He²⁺

13. The radiation which has highest penetrating power is

1. α-rays
2. β-rays
3. γ-rays
4. None of the above

Answer: γ-rays

14. Isotopes are having

1. Same atomic number but different mass number
2. Same atomic number and same mass number
3. Atomic number increases
4. None of the above

Answer: Same atomic number but different mass number

15. When the difference between mass number and atomic number of atoms of two or more elements are same, the atoms are known as

1. Isotopes
2. Isobars .
3. Isotones
4. Nuclear isomers

Answer: Isotones

16. Half-life period of a radioactive is calculated by:-

Answer: a)

17. The atomic number of the element is equal to the

1. Number of protons
2. Number of neutrons
3. Slim of number of protons & neutrons
4. None of the above

Answer: Number of protons

18. P- rays are

1. +vely charged
2. -vely charged
3. Neutral
4. None of the above

Answer: -vely charged

19. During the emission of a P-particle:-

1. Atomic number increases by 1 unit & there is no change in the mass number
2. Atomic number decreases by 2 unit, mass number decreases by 4 unit
3. Atomic number and mass number remains same
4. Atomic number and mass number both get increased

Answer: Atomic number and mass number remains same

20. P-10 gas is

1. Mixture of 10% argon and 90% methane
2. Mixture of 90% argon and 10% air
3. Mixture of 90% argon and 10% oxygen
4. Mixture of 90% argon and 10% methane

Answer. mixture of 90% argon and 10% methane

21. The energy resolution of the proportional counter is in the range of

1. 1-5%
2. 5-7%
3. 5-15%
4. 5-10%

Answer: 5-10%

22. The function of quenching vapour are:-

1. To ionise the ionising radiation
2. Produce amplitude for incident radiation
3. To prevent the false pulses
4. All of the above

Answer: To prevent the false pulses

23. Which is the commonly used quenching agent?

1. Chlorine & Bromine
2. Methane
3. Argon
4. Alcohol

Answer: Chlorine & Bromine

24 Which one of the following is not the gas-filled detector?

1. Ionisation chamber
2. Proportional counter
3. Geiger-Muller counter
4. Scintillation detector

Answer: Scintillation detector

25. Molecular formula of Barium sulphate is:-

1. BaSO₄
2. Ba₂SO₄
3. Ba(SO₄)₂
4. BaSO₃

Answer: BaSO₄

Antimicrobials

An antimicrobial (disinfectant and antiseptic) is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi or protozoans ntimicrobial drugs either kill microbes (microbiocidial) or prevent the growth of microbes (microbiostatic).

Specific terminology describes exact mode or mechanism of action.

Antiseptics: Antiseptic is a substance that prevents or arrests the growth of action of microorganisms. It acts by inhibiting their activity or destroying them especially of agents applied to living tissue like surface of skin, application of antiseptic dressings on wounds.

The drugs like phenol, iodine, boric acid, cetrimide are the examples of antiseptics.

Disinfectants: These are the drugs or substances used either to kill bacteria or prevent their growth or multiplication. It is used on non-living objects or outside the body.

For example : Disinfection of surgical instruments, sputum and urine containers on floor. Commonly used as disinfectants includes cresol, phenol.

Germicides: These are the substances which kill microorganisms. They act by oxidation of bacterial protoplasm, by denaturation of bacterial enzymes and proteins, by increasing permeability of bacterial cell membrane.

Potency of germicide is expressed by Phenol Coefficient. Specific terminology like bacteriocide (against bacteria), fungicide (against fungi), virucide (against virus) etc. denotes exact action.

Bacteriostatics: These are the substances which primarily function by inhibiting the growth of bacteria. Thus, bacteriostatic drugs or agents do not kill but arrest the growth of bacteria.

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Sanitizers: Sanitizer is the process of rendering sanitary by reducing the number of bacterial contaminants. These are used to maintain general public health standards.

Santization can be achieved only with surfaces and articles that are physically clean in addition to possess low bacterial counts or that are free from most vegetative microbes.

High cone, of sanitizers also cause local cellular damage. Inorganic compounds generally exhibit antimicrobial action by involving either of the following three mechanisms :

1. Oxidation
2. Halogenation
3. Protein precipitation.

Boric Acid

Chemical Formula: H₃BO₃

Molecular Weight: 61.83

Synonyms : Hydrogen borate, boracic acid, orthoboric acid, acidum boricum.

It is widely distributed in sea water, plants and fruits. It is also available in the combined form as its largest natural source.

Method of Preparation

It is prepared by reading hydrochloric or sulphuric acid with the native borax.

The solution is filtered. The crystals obtained are washed and then allowed to dry at room temperature.

Properties

1. It occurs as colourless or white crystals.
2. It is slightly soluble in water and in alcohol.
3. It is odourless with slightly acidic and bitter taste.
4. On heating, it decomposes to form metaboric acid HBOr

Uses: Boric acid can be used as an antiseptic for minor bums or cuts. It is used in dressings or salves. It is applied in a very dilute solution as an eye wash. As an antibacterial or antimicrobial compound, it can also be used as an acne treatment.

Borax

Chemical Formula: Na₂B₄O₇.10H₂O

Molecular Weight: 381.4

Synonyms

Sodium Borate, Sodium Tetraborate, Sodium pyroborate

Properties

It occurs as colourless crystalline or white crystalline powder. It is having saline and alkaline taste. It loses all its water of crystallisation on ignition. It is odourless.

It efflorescences in dry air. It reacts with zinc salts to give zinc borate. Acidified and aqueous solution of sodium tetraborate on heating yield crystals of botfc acid.

Uses
It finds use externally for eye washes and also used as an emulsifying agent for certain oils.

It is also used for softening of water.

Hydrogen Peroxide

Chemical Formula: H₂O₂

Molecular Weight: 34.016

It is an aqueous solution of hydrogen peroxide. It is having not less than 6% w/w of H O. which corresponds to about 20 times its volume of available 2: oxygen.
It was discovered by French chemist Thenard.

Methods of Preparation

In laboratory, it is prepared by Merck’s process. It is prepared by adding calculated V amounts of sodium peroxide to ice cold dilute (20%) solution of H₂SO₄.

It is also prepared by the action of sulphuric acid or phosphoric acid on hydrated barium peroxide Ba02.8H20

On commercial scale, H202 can be prepared by the electrolysis of 50% H2S04 solution. In a cell, peroxy sulphuric acid is formed at the anode.

It is also obtained by decomposing barium peroxide with phosphoric acid or by passing carbon dioxide through a solution of barium peroxide in water.

Properties

Hydrogen peroxide is clear, colourless syrupy liquid. It is odourless or may have an odour resembling to that of ozone unstable liquid. It has a specfic gravity of about 1.463 at 0°C. It is a strong oxidizing agent. It is soluble with water from which it can be extracted with solvent ether. It rapidly decomposes in contact with oxidizable organic matter and with metals.

Storage

H2O2 is not stored in glass bottles since the alkali metal oxides present in glass catalyse its decomposition It is stored in paraffin wax coated with glass, plastic or teflon bottles. Small amounts of acid, glycerol, alcohol, acetanilide and H3P04 often used as stabilizers to check its decomposition.

Uses

It acts as an antiseptic and a germcide and hence is used for cleaning cuts and wounds. It is used for bleaching delicate articles like wool, hair, feather, ivory etc. It is used as an aerating agents in production of spong rubber. It is used as an antichlor. It finds use in deodorants. It is also used for cleaning ears and removing the surgical dressing. It is an effective antidote for phosphorous and cyanide poisoning.

Potassium Permanganate

Chemical Formula: KMnO₂

Molecular Weight: 158.03

It is an inorganic chemical compound having not less than 99.0% of KMnO₂. Formerly known as Permanganate of Potash or Candy’s Crystals.

Method of Preparation

On large scale, it is prepared by mixing a solution of KOH with powdered manganese oxide and potassium chlorate in the presence of air or an oxidizing agent.

Potassium manganate so formed is extracted along with boiling water and a current of chlorine, C02 or ozonised air is passed into the liquid untill it gets converted to permanganate. The MnO₂ formed is removed.

When carbon dioxide is passed through the chlorine solution, manganate gets converted into KMnO₄

The solution of KMn04 is drawn off from any precipitate of Mn02 which is then concentrated and crystallized. The crystals are then centrifuged and dried.

Properties

It occurs as odourless dark purple or almost black prismatic crystals or granular powder. It has a sweet and astringent taste. It decomposes with a risk of explosion, in contact with certain organic substances.

It has a specific gravity of about 2.703. It is stable in air. It is soluble in water. When it is heated, it decomposes at a high temperature of about 240°C

Alkaline or neutral solution of potassium permanganate is able to oxidize iodide to iodate

In acidic medium iodine gets liberated from iodates.

Uses

It finds use in the treatment of urethritis. It possesses oxidizing properties and oxidizes proteins and other bioorganic substance. It has the capability to destroy the poison and prevents absorption.

Its solutions are used to clean the ulcer or abscesses, as wet dressings and in baths in eczematous condition. It finds use as an antidote in the case of poisoning by barbiturates, chloral hydrate and many alkaloids.

Chlorinated Lime Or Bleaching Powder Ca(OcI)CI

Chemical Formula : Ca(C1O)₂

Molecular Weight: 136.98

Synonyms: Bleaching powder, chloride of lime.

Method of Preparation

It is prepared by the chlorination of slaked lime.

It is usually a mixture of calcium hypochlorite (Ca(OCl)₂) and calcium chloride with some slaked lime

Properties
It is dull white powder with characteristic odour. It is slightly soluble in water and in alcohoi. On exposure to air, it becomes moist and gradually decomposes with the loss of chlorine.

Its aqueous solution is strongly alkaline. It is able to oxidize many salts such as manganous salts to permanganate. Carbon dioxide gets absorbed and chlorine is evolved.

Uses

It is also used as an ingredient in bleaching powder, used for bleaching cotton and linen. It is also used in sugar industry for bleaching sugar-cane juice before its crystallization.

It is used as a sanitizer in outdoor swimming pools in combination with a cyanuric acid stabilizer which reduces the loss of chlorine due to ultraviolet radiation. It has the bactericidal action.

Iodine

Chemical Formula: I₂

Molecular Weight: 253.8

Iodine I is a dark violet non-metallic halogen element.

Method of Preparation

Iodine is manufactured by extracting kelp (sea weed’s ash) with water. The solution is concentrated when the sulphate and chloride of sodium and potassium get crystallized out, leaving freely soluble sodium and potassium iodides in the mother liquor.

Sulphuric add is added to the mother-liquor which then gets decanted off.

In the laboratory, it reacts by heating potassium iodide or sodium iodide with dilute sulphuric add and manganese dioxide.

Properties

It occurs as heavy, bluish-black or greyish violet brittle plates with a metallic lusture. It is very slightly soluble in alcohol, chloroform and slightly soluble in concentrated solutions of iodides, carbon disulphide, solvent ether, carbon tetrachloride, chloroform, give violet solutions.

Uses

It is used as an anti-hyperthyroid. It is used in the manufacture of dyestuffs and drugs. It is used as a reagent in analytical chemistry. It is used in the manufacture of compounds used in Photography.

Prolonged use of iodine may produce metallic taste, increased salivation, burning pain. It can give rise to allergic reactions also.

Silver Nitrate

Chemical Formula: AgNO₃

Molecular Weight: 169.89

It contains not less than 99.5% and not more than the equivalent of 100.5% of AgNO₃.

Preparation

It is prepared by the reaction of silver with nitric acid which results into the formation of silver nitrate.

Properties

It occurs as colourless or white, odourless rhombic crystals. It is having a bitter caustic or metallic taste. It is highly soluble in boiling water when exposed to light or organic/blunder matter, it turns into grey or greyish black colour due to its reduction in metallic silver.

Uses

Silver salts have antiseptic properties. It is widely used as an astringent and germicide. Dilute solution of AgNO₃ used to be dropped into new bom babies at birth to prevent contraction of gonorrhea from the mother.

Eye infection and blindness of new bom reduced by this method, incorrect damage, however could cause blindness in extreme cases.

Povidone-Iodine (Pv-I)

It is a stable chemical complex of Polyvinyl Pyrfolidonfe (povidone, PVP) and Elemental Iodine. It contains 9.0% to 12.0% available iodine, calculated on a dry basis. It belongs to iodophors class of compounds.

Properties

It is having a slight characteristic odour. It is a yellowish-brown amorphous powder. It is soluble in water and in alcohol but practically insoluble in organic solvents. It is acidic litmus.

Uses

It has a broad spectrum antiseptic for topical application in the treatment and prevention of infection in wounds. It is used as a disinfectant. It is also used as gargles and mouthwashes for the treatment of infections in the oral cavity.

Silver Protein

Chemical Formula: Variable

Molecular Weight : 169.89

Method of Preparation

It is obtained by treating silver salts with an excess of denaturated protein. The product is then dried in vaccum and finally stored in amber coloured bottles.

Properties

It occurs as dark brown or almost black shinning scales or granules. It is odourless and hygroscopic in nature. It is freely soluble in water but almost insoluble in alcohol, chloroform and ether.

When dissolved in water it forms colloidal solutions. It is affected by light and, therefore, should be protected from light. Mild silver protein solution in nitric acid yields a precipitate of silver chloride.

Uses

It is found to be useful in the treatment of infections of the respiratory tract through the prophylactic use which has been discontinued due to harmful nature. It possess to have mild antibacterial properties.

Mercury

Chemical Formula: Hg

Molecular Weight: 200.6

Synonym: Hydragyrum, Quick-silver

The Principle ore of Mercury is a red sulphide mineral called Cinnabar, HgS. It also occur as an amalgam of silver and gold and in small globules through rocks.

Preparation

It is obtained by roasting cinnabar in a current of air.

The free mercury gets liberated and further it gets purified by volatilisation or chemically by dropping mercury into a column of dilute nitric acid for removing basic impurities.

Properties

It occurs as shiny, silvery heavy liquid. It gets easily converted into the shape of globules. It readily volatiles on heating, its melting point is -38.9°C.

It is almost insoluble in water, alcohol and hydrochloric acid. It gets easily reacted by centrated sulphuric acid which results into the evolution of sulphuric dioxide and formation of mercuric sulphate.

Uses

It is used as a Pharmaceutical Aid. It has Carthatic and Parasitic action. Its solution of salts have violent corrosive effects on skin and mucous membrane, nausea, vomiting, abdominal pain, bloody diarrhoea, kidney damage and death.

Compounds of mercury and its salts have declined greatly during this century.

Note

Avoid frequent or prolong contact of mercury with the skin. Mercury spills (zuhether in laboratory or in house from broken thermometer etc.) should be handled and collected with special care.

Yellow Mercuric Oxide

Chemical Formula: HgO

Molecular Weight: 216.16

Preparation

It is prepared by precipitation of mercuric nitrate or mercuric chloride with sodium hydroxide solution. The yellow precipitate obtained gets settle down and further washed by decantation.

It gets filtered and re-washed to separate chloride and further gets dried off in air.

As the yellow precipitates gets affected by light, that is if all the reactions should be carried out in dark to maintain its orange yellow colour.

Properties

It is odourless orange yellow amorphous powder. Its colour varies from orange to yellow according to the temperature at which it is prepared. It gets decolourised on exposure to light. It is insoluble in water and alcohol but soluble in acids sch as HCl or H₂SO₄.

Uses

It has been used as a topical antiseptic, in conjunctivitis and in chronic ulcers. Due to its insolubility, it slowly releases Hg₂+ ions which has mild sustained local antibacterial properties.

It is used in eye ointments for the local treatment of minor infections and inflammation of the eye including conjunctivitis.

Ammoniated Mercury

Chemical Formula: NH₂HgCl

Molecular Weight: 252.1

Synonym

Aminochloride of mercury, White precipitates.

Preparation

It is prepared by adding an aqueous solution of mercury chloride to ammonia solution with constant stirring. The precipitates so obtained gets filtered off and then washed with cold water to remove ammonium chloride. It is dried at a temperature not exceeding 30°C.

Properties

It is a white heavy amorphous powder. It is odourless. It is almost insoluble in water, alcohol and ether but it is readly soluble in warm acetic acid. It is stable in air. It darkens on exposure to light.

It gets decomposed when dissolved in cold water. In boiling water, it gets hydrolyzed to yellow basic compound :- NH₂HgCl; HgO

Uses

It is used in the treatment of skin diseases such as impetigo, in crab infections. Adverse effects include allergic reactions and mercury poisoning

Zinc Undecylenate

Chemical Formula : [CH₂ = CH (CH₂ )₈ COO]₂ Zn

Molecular wt: 431.9

Synonyms

Zinc Undecenoate, Zinc undec-10-enoate, Zinc undecyl.

Preparation

It is prepared by precipitation from a solution of sodium salt.

Properties

It is a fine white powder. It is stable and is practically insoluble in water and in alcohol.

Uses

It is topical antifungal agent.

Sodium Antimony Gluconate

Chemical Formula: C₆H₈NaO₇Sb

Molecular Weight:‘336.88

Synonym: Antimony Sodium Gluconate

Method of Preparation

It is prepared by the action of sodium hydroxide on antimony trichloride and a solution of gluconic acid.

Properties

It is an odourless, white amorphous powder. It is soluble in water but insoluble in alcohol and solvent ether. Solution of Antimony Gluconate should be prepared immediately before use.

Uses
It is used in the treatment of leishmaniasis (Kala-azar) and as antischistosomal.

Antimicrobials Short Answer Questions

Question.1. Define Antimicrobials?
Answer. An antimicrobial (disinfectant and antiseptic) is a substance that kills or inhibits the growth of microorganism such as bacteria, fungi or protozoans.

Question.2. Classify antimicrobials on the basis of the exact mode or mechanism of action?
Answer.

1. Antiseptic Bacteriostatics
2. Disinfectant Sanitizers
3. Germicides

Question.3. Define Antiseptic?
Answer. Antiseptic is a substance that prevents or arrests the growth of action of microorganisms.

Question.4. How do antiseptics act?
Answer. Antiseptics act by inhibiting the activity of microorganism or destroying them especially of agents applied to living tissues like surface of skin, application of antiseptic dressing on wounds.

Question.5. Write down the two examples of antiseptics?
Answer. Iodine, Boric acid, Cetrimide.

Question.6. Define Disinfectants?
Answer. Disinfectants are the drugs or substances used either to kill bacteria or prevent their growth or multiplication.

Question.7. Write down the two examples of disinfectants?
Answer. Cresol, Phenol.

Question.8. What is the difference between antiseptics and disinfectants?
Answer.

Antiseptics

1. It is a substance that prevents or arrests the growth of microorganism.
2. It is applied on living tissues.

Disinfectants

1. It is a substance used either to kill bacteria or prevent their growth or multiplication. ,
2. It is applied on non-living surfaces.

Question.9. What do you understand by the term Germicide? How do they act?
Answer. Germicides are the substances which kill micro-organisms.

Germicide act by oxidation of bacteria protoplasm, by denaturation of bacteria, enzymes and proteins.

Question.10. What is Bacteriostatic?
Answer. These are the substances which primarily function by inhibiting the growth of bacteria. Thus, bacteriostatic agents or drug do not kill but arrest the growth of bacteria.

Question.11. What do you understand by ‘Sanitizers’?
Answer. Sanitizer is the process of rendering sanitary by reducing the number of bacterial contaminants.

Question.12. Enlist various inorganic compounds that are used as Anitmicrobials?
Answer. Boric add, Borax, Hydrogen peroxide, Potassium permanganate, Chlorinated lime,Iodine.

Question.13. What is the chemical formula of Boric acid?
Answer. Chemical formula of Boric add is H₃BO₃.

Question.14. What is the method of preparation of Boric Acid?
Answer. Boric add is prepared by reacting hydrochloric or sulphuric add with the native borax to product orthoboric add.

The solution is then filtered off and the crystals obtained are washed and then allow to dry at room temperature.

Question.15. What is the chemical formula of Borax? By which other names they are known in the market?
Answer.

Borax: Na₂B₄O7.10H₂O

Synonyms: Sodium borate, Sodium tetraborate, Sodium pyroborate

Question.16. What is the method of preparation of Hydrogen Peroxide?

Answer: Hydrogen peroxide is prepared by Marck’s process. It is prepared by adding calculated amounts of sodium peroxide to ice cold dilute (20%) solution of H₂SO₄.

Question.17. Enlist the pharmaceutical uses of Hydrogen Peroxide?
Answer. Hydrogen peroxide is used as an antiseptic and a germicide. It is also used for cleaning cuts and wounds. It is an effective antidote for phosphorous and cyanide poisoning.

Question.18. What is the chemical formula and method of preparation for Potassium permanganate?
Answer. Chemical formula of potassium permanganate is KMnO₄.

Potassium permanganate is prepared by mixing a solution of KOH with powdered manganese oxide and potassium chlorate in the presence of air or an oxidising agent and the mixture gets boiled.

Question.19. What are the Pharmaceutical uses of Potassium Permaganate?
Answer. Potassium permaganate solution is used to clean the ulcer or abcesses, as wet dressings and in baths of eczematous condition

Question.20. What is the chemical formula of Chlorinated Lime?
Answer. Ca(ClO)₂

Question.21. What are the uses of Iodine?
Answer. Iodine is used as an antihyperthyroid. It is also used in the manufacture of dye stuffs and drugs.

Question.22. What is the method of preparation of Iodine in laboratory?
Answer. In laboratory, Iodine reacts by heating potassium iodide or sodium iodide wth dilute sulphuric acid and manganese dioxide.

Question.23. What is the general formula of Silver nitrate?
Answer. AgNO₃

Question.24. What is the method of preparation of Silver nitrate?
Answer. Silver nitrate is prepared by the reaction of silver with nitric acid which result in the formation of silver nitrate.

Question.26. What are the other names of Mercury?
Answer. Hyedragyrum, Quick-silver.

Question.27. How do we prepare Mercury?
Answer. Mercury is obtained by roasting cinnabar in a current of air.

The free mercury gets librated and further it gets purified by volatilisation.

Question.28. What is the chemical formula of yellow mercuric oxide?
Answer. HgO.

Question.29. What is the chemical formula of Ammoniated Mercury?
Answer. NH₂HgCl.

Question.30. How do we prepare ammoniated mercury?
Answer. Ammoniated mercury is prepared by adding an aqueous solution of mercury chloride to ammonia solution with constant stirring. The precipitates are obtained.

Question.31. How do antimicrobials act?
Answer. Antimicrobial act by either oxidation, halogenation and protein precipitation.

Antimicrobials Fill In The Blanks

1. Antimicrobial is a substance that……………………

Answer: Kills or inhibits bacteria

2. Antimicrobial agents act by ………………….

Answer: Oxidation, halogenation and protein precipitation

3. Antiseptic are applied to…………… while disinfectants are applied to……………….

Answer: Living tissues, non-living objects

4………………..is the process of rendering sanitary by reducing the number of bacterial contaminants.

Answer: Sanitization

5. KMnO₄can be used as an…………………………

Answer: Bactericidal, fungicidal, in the treatment of urethritis

6. KMnO₄ is………………… reducing agents.

Answer: Strong oxidizing agent

7. Povidone-iodine is a member of class compound referred to as…………………………….

Answer: Iodophors

8. Povidone-Iodine is……………………………

Answer: Polyvinyl pyrollidine

9. Solution of AgNO₃ can be used as an………………………

Answer: To prevent contraction of gonorrhea

10. Chemical formula of Ammoniated mercury is……………………

Answer: NH₂HgCl

11. Ammoniated mercury is also known as…………………………

Answer: Aminochloride of mercury

12. …………………….include antiseptic, germdde and- disinfectant agent as well as sanitization process.

Answer: Iodine

13………………… give rise to hyperthyroidism symptoms of which are extreme fatigue,goitre.

Answer: Iodine

14. Diluted hydrogen peroxide (3% and 12%) is used to bleach human hair when mixed with ammonia and is called as…………………….

Answer: Peroxide blonde

15. Potassium permaganate is manufactured on a large scale by heating…………………. in the presence of air or as an oxidizing agent such as

Answer: Potassium hydroxide with manganese oxide, potassium nitrate

16. Yellow mercuric oxide is prepared by precipitation of………………………………..with………………….

Answer: Mercuric nitrate with sodium hydroxide

17. Mercury compounds as antimicrobial agents are . …………………..

Answer: Ammoniated mercury, yellow mercuric oxide

18. The chemical formula of Ammoniated Mercury is……………………..

Answer: NH₂HgCl

19. Ammoniated mercury is also known as ………………………….

Answer: Aminochloride of mercury, white precipitates

20 ………………………..is prepared by precipitation of a solution of sodium salt.

Answer: Zinc undecylenate

21. The chemical formula of Sodium Antimony Gluconate is……………………..

Answer: C₆H₈NaO₇Sb

22. Antimony gluconate is used as………………..

Answer: Antischistosomal

23……………………is prepared by reacting hydrochloric or sulphuric add. with the native borax to produce orthoboric add.

Answer: Boric acid

24. Hydrogen peroxide is…………………….solution.

Answer: Aqueous

25. ………….is an effective antidote for cyanide poisoning which is also used as an antimicrobial.

Answer: Hydrogen Peroxide

 

 

Inorganic Chemistry Practicals

 Inorganic Chemistry Experiment No. 1

Aim:- To prepare and standardize 1 M sodium hydroxide (NaOH) solution.

Requirements:-

Chemicals required:- Sodium hydroxide, potassium biphthalate, phenolphthalein indicator.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Procedure:-

Preparation:

1. Add about 4.2 gm of sodium hydroxide with continuous stirring.
2. Add more about 700 ml of distilled water, mix and allow to cool to room temperature.
3. Make up the volume 1000 ml with distilled water. Mix solution thoroughly.

Sodium Hydroxide Solution Standardization:

1. Accurately weigh about 0.5 gm of potassium biphthalate, previously crushed lightly and dried at 120°C for 2 hrs.
2. Dissolve in 75 ml of carbon dioxide free water.
3. Add 2 drops of phenolphthalein, and titrate with sodium hydroxide solution to the production of a permanent pink colour.
4. Each 20.42 mg of potassium biphthalate is equivalent to 1 ml of 0.1 N sodium hydroxide.

Calculation:

Read and Learn More Pharmaceutical Inorganic Chemistry Notes

M = Wt. of potassium biphthalate (gm) / 0.20423 * NaOH solution (ml)

 Inorganic Chemistry Experiment No. 2

AIM: TO Prepare and standardize 1 M hydrochloric acid (HCl) solution.

Requirements:-
.
Chemicals required:- sodium carbonate, hydrochloric acid, methyl indicator indicator.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Procedure:-

Preparation
.
Dilute 85 ml of hydrochloric acid with water to produce 1000 ml.

Standardization

1. Weigh accurately about 1.5 gm of anhydrous sodium carbonate, previously heated to about 270°C for 1 hour.
2. Dissolve it in 100 ml of water and add 0.1 ml of methyl red solution.
3. Add the acid slowly from a burette, with constant stirring, until the solution become faintly pink.
4. Heat the solution to boiling and titrate further as necessary until the faint pink colour is no longer affected by continued boiling.
5. 1 ml of 1 M hydrochloric acid is equivalent to 0.05299 gm of Na₂CO₃.

Calculation

M=Na₂CO₃(mg) / HCl (ml) * 52.99

 Inorganic Chemistry Experiment No. 3

Aim:- To prepare and standardize 0.1 N potassium permanganate (KMnO₄) solution.

Requirements:-

Chemicals required:- Potassium permanganate, sodium oxalate, sulphuric acid, methyl indicator.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Procedure:-

Preparation

1. Dissolve 3.3 g of reagent grade potassium permanganate (KMnO₄) in 1 L of purified water and heat on a steam bath for two hrs.
2. Cover and allow to stand for 24 hrs.
3. Filter through a fine porosity sintered glass crucible, discarding the first 25 mL. Store in a glass-stoppered, amber-colored bottle.
4. Avoid exposure to direct sunlight; cover the neck of the bottle with a small beaker as protection against dust.

Standardization

1. Weigh accurately 0.2-0.3 g sodium oxalate (Na₂C₂O₄) (dried 2 hrs., 105-110 °C).
2. Cool in a desiccator and transfer quantitatively to a 600 mL beaker.
3. Add 250 mL of purified water (freshly boiled and cooled) and 10 mL sulphuric acid (96% H₂S0₄, sp g 1.84).
4. Add rapidly from a burette about 95% of the theoretical quantity of potassium permanganate solution needed; stir until the solution is clear.
5. Heat the solution to 55-60 °C (Maintain temperature range during titration.) and complete the titration by slow drop wise addition until the appearance of a pink color whibh persists for 30 secs.
6. Determine and subtract a blank titration run at 55-60 °C on a mixture of 250 mL of purified water (freshly boiled and cooled) and 10 mL of concentrated sulfuric acid.

Calculation

N= wt. of Na₂C₂O₄(gm) *1000 /(Net Titre ml.) * 67.00

 Inorganic Chemistry Experiment No. 4

Aim- To prepare and standardize 1 N sodium thiosulphate (Na₂S₂O₃) solution.

Requirements:-

Chemicals required:- Sodium thiosulphate, potassium dichromate, cone, hydrochloric acid , potassium iodide.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Procedure:-

Preparation

1. Dissolve 25 g of sodium thiosulphate pentahydrate (Na2S203*5H20, 248 g/mol) in 1 liter of freshly boiled distilled water.
2. For improve its stability by adding 0.1 g of Na2C03.
3. Store overnight, and filter through fine grade paper, collect and store in a clean, dark glass bottle.

Standardization

1. About 1.25gm of potassium dichromate is weighed out into a 250ml standard flask.
2. It is dissolved in water & made up to the mark.
3. 20ml of the made up solution is pipette out into a conical flask.
4. About 3ml of concentrated HC1 is added, followed by 5ml of 10% potassium iodide solution.
5. It is titrated against sodium thiosulphate solution from the burette using starch as indicator.
6. Titration is repeated till concordant values are obtained.

Calculation

N= wt. of K₂Cr₂O₇ (mg)/49.04 * Na₂S₂O₃ (ml)

 Inorganic Chemistry Experiment No. 5

Aim:- To prepare and standardize .05 M disodium edetate (EDTA) solution.

Requirements:-

Chemicals required:- Disodium edetate, zinc, ammonia, sodium hydroxide, mordant black II .

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Procedure:-

Preparation

Dissolve 18.6 g of disodium edetate in sufficient water to produce 1000 ml.

Standardization

1. Weight accurately about 0.8 g of Granulated Zinc, dissolve by gentle warming in 12ml of diluted Hydrochloric acid and 0.1ml of bromine solution boil to remove the excess bromine, cool, add sufficient water to produce 200 ml.
2. Pipette 20 ml in to a conical flask and nearly neutralize with 2 M sodium hydroxide.
3. Add about 125 ml water and sufficient ammonia buffer pH 10 to dissolve the precipitate and add 5 ml in excess.
4. Add 50 mg of mordant black II mixture and titrate with the prepared disodium edentate solution until the solution turns to green point.

Calculation

M = wt. of Zinc (gm) * 20/ 200 * 0.00654 * volume of EDTA (ml)

 Inorganic Chemistry Experiment No. 6

Aim:- Prepare and standardize 0. 1 M silver nitrate (AgNO₃) solution.

Requirements:-

Chemicals required:- Silver nitrate, acetic acid, methanol, sodium hydroxide, Eosin Y indicator

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Procedure:-

Preparation

1. Take about 100 ml of water in a clean dried 1000 ml volumetric flask.
2. Add about 17 gm of silver nitrate with continuous stirring.
3. Add more about 700 ml of distilled water, mix.
4. Make up the volume 1000 ml with water.
5. Mix solution thoroughly.
6. Keep the solution for at least one hour and then carry out the standardization.

Standardization

1. Transfer about 50 mg, accurately weighed sodium chloride, previously dried at 110°C for 2 hours, to a 150 ml conical flask.
2. Dissolve in 5 ml of distilled water.
3. Add 2.5 ml of acetic acid, 25 ml methanol and about 0.25 ml of Eosin Y indicator.
4. Stir with a magnetic stir.
5. Titrate with the silver nitrate solution.

Calculation

M= NaCl (mg) / AgNO₃ (ml) * 58.44

Primary And Secondary Standards

Primary Standard

A primary, standard is a reagent that is extremely pure, stable, it not a hydrate/has no water of hydration, and has a high molecular weight.

A primary standard should:

• Be easy to store without deteriorating or reacting with that atmosphere.
• Be readily obtainable in pure form.
• Be in expensive.

Examples of primary standards for titration of acids are:

• Sodium carbonate: Na₂CO₃, mol wt. = 105.99 g/mol
• Tris-(hydroxymethyl)aminomethane (TRIS or THAM): (CH₂OH)₃CNH₂, mol wt. =121.14 g/mol

Examples of primary standards for titration of bases are:

• Potassium hydrogen phthalate (KHP): KHC₈H₄O₄, mol wt. = 204.23 g/mol
• Potassium hydrogen iodate: KH(IO₃)₂, mol wt. = 389.92 g/mol

Examples of primary standards for redox titrations are:

• Potassium dichromate: K₂Cr₂O₇, mol wt. = 294.19 g/mol
• odium oxalate: Na₂C₂O₄ mol wt. = 134.00 g/mol

Secondary Standard

A secondary standard is a standard that is prepared in the laboratory for a specific analysis. U is usually standardized against a primary standard.

Example:

An unknown solution of HC1 may be standardized volumetrically in two ways, namely:

• By the help of ‘AnalaR’-grade Na₂CO₃ i.e., purity is known-primary Standard’, and
• By the help of another standard solution of NaOH—‘Secondary Standard’,

Acid-Base Titrations

Acid-base titration is based on the neutralization reaction between acid and base. In this titration, the endpoint is a condition at which the moles of acid exactly cancel out the moles of base present in a solution or vice-versa. Hence the solution is neutral.

We can use the colour indicator like litmus paper and phenolphthalein to determine the endpoint. Potassium hydrogen phthalate calcium carbonate and oxalic acid strength of sample solution.

 Inorganic Chemistry Experiment No. 7

Aim:- To perform the assay of boric acid as per I.P.

Requirements:-

Chemicals required:- Boric acid (sample), sodium hydroxide, glycerol, phenolphthalein
indicator.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- Boric acid is very weak acid with very less dissociation constant. When it reacts with glycerol, glyceroboric acid is formed and its dissociation constant is increased and it behaves like strong acid.

Given sample of boric acid is dissolved in mixture of water and glycerin (1:2) and titrated against sodium hydroxide. End point can be detected by using phenolphthalein as an indicator.

Reaction involved in this titration is as follows.

Procedure:-

Preparation of reagents and solutions:-

Preparation and standardization of sodium hydroxide (1 M)

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the NaOH solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the NaOH solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the NaOH solution.
3. Weigh accurately about 1.0 g of H₂BO₃ in a conical flask and dissolve in mixture of 25 ml water and 50 ml glycerol.
4. Add 2 drops of phenolphthalein indicator.
5. Then fill the burette with standardized NaOH solution.
6. Start titration with the NaOH until reach the endpoint. The first titration should be performed by adding 0.50 ml portions of NaOH solution from burette, with swirling. The approach of the endpoint is suggested by the temporary appearance of a pink colour that fades when the solution is swirled for upto 10 seconds. A pink colour that persists for more than 30 seconds signals the actual endpoint.
   Note:- The solution may lose its colour after 30 seconds or more, but it is not considered.
7. The first titration gives a rough idea of the amount of NaOH needed to neutralize the H₃BO₃.
8. Record the reading of burette.
9. Repeat the titration three times to get precise readings. For these we can add about 70% of the needed NaOH quickly and then, near the end, add NaOH one drop at a time until the endpoint is observed.
10. Take mean of them and calculate the percentage purity of H₃BO₃.

Observation Table:-

Calculations:-

Percentage purity = V X E X AM X 100/W x RM

Where,
V = volume of NaOH used (ml).
E = equivalent factor.
AM = actual molarity.
RM = required molarity.
W = weight of sample (g).

NOTE: The equivalent factor of H₃BO₃ for 1 ml of 1 M NaOH is 0.06183.

Result:- The percentage purity of boric acid was found to be

 Inorganic Chemistry Experiment No. 8

Aim:-  perform the assay of ammonium chloride as per I.P.

Requirements 

Chemicals required:- Ammonium chloride (sample), sodium hydroxide, glycerol,phenolphthalein indicator.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- Ammonium chloride is an expectorant, diuretic and systemic acidifier. It is an acidic salt which reacts with formaldehyde to liberate free acid, that free acid reacts with sodium hydroxide. End point can be detected by using phenolphthalein as an indicator. Reaction involved in this titration is as follows.

Procedure

Preparation and  standardization of sodium hydroxide (0. 1 M):-

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the NaOH solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the NaOH solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the NaOH solution.
3. Weigh accurately about 0.1 g of NH₄CI in a conical flask and dissolve in 20 ml distilled water.
4. Add a mixture of 5ml formaldehyde solution and 20 ml distilled water.
5. Add 2 drops of phenolphthalein indicator and allow to stand for two minutes.
6. Then fill the burette with standardized NaOH solution.
7. Start titration with the NaOH until reach the endpoint. The first titration should be performed by adding 0.50 ml portions of NaOH solution from burette, with swirling. The approach of the endpoint is suggested by the temporary appearance of a pink colour that fades when the solution is swirled for upto 10 seconds. A pink colour that persists for more than 30 seconds signals the actual endpoint
   Note:- The solution may lose its colour after 30 seconds or more, but it is not considered.
8. The first titration gives a rough idea of the amount of NaOH needed to neutralize the free HCl.
9. Record the reading of burette.
10. Repeat the titration three times to get precise readings. For this we can add about 70% of the needed NaOH quickly and then, near the end, add NaOH one drop at a time until the the endpoint is observed.
11. Take mean of them and calculate the percentage purity of NH₄CI

Observation Table:

Calculations:-

Percentage purity = V x E X AM x 100/ W X RM

Where,
V = volume of NaOH used (ml).
E = equivalent factor.
AM = actual molarity.
RM = required molarity.
W= weight of sample (g).

NOTE: The equivalent factor of NH₄Cl for 1 ml of 0.1 M NaOH is 0.005349.

Result: The percentage purity of ammonium chloride was found to be

 Inorganic Chemistry Experiment No. 9

AIM:- To perform the assay of sodium carbonate as per I.P.

Requirements.-

Chemicals required:- Sodium carbonate (sample), sodium hydroxide, methyl orange indicator.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

PRINCIPLE:- Given sample of sodium carbonate is dissolved in water and titrated against hydrochloric acid. End point can be detected by using methyl orange as an indicator.

Reaction involved in this titration is as follows.

PROCEDURE:-

Preparation of reagents and solutions:-

Preparation and standardization of hydrochloric acid (1 M):-

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the HCl solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the HCl solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the HCl solution.
3. Weigh accurately about 1.0 g of Na₂CO₃ in a conical flask and dissolve in 25 ml distilled water.
4. Add 2 drops of methyl orange indicator.
5. Then fill the burette with standardized HClsolution.
6. Start titration with the HCl until reach the endpoint. The first titration should be performed by adding 0.50 ml portions of HCl solution from burette, with swirling. The approach of the endpoint is suggested by the temporary appearance of a pink colour that fades when the solution is swirled for uplo I0 seconds. A pink colour that persists for more than 30 seconds signals the actual endpoint.
   Note:- The solution may lose its colour after 30 seconds or more, but it is not considered.
7. The first titration gives a rough idea of the amount of HCl needed to neutralize the Na₂CO₃.
8. Record the reading of burette.
9. Repeat the titration three times to gel precise readings. For this we can add about 70% of the needed HCI quickly and then, near the end, add HCI one drop at a time until the endpoint is observed.
10. Take mean of them and calculate the percentage purity of Na₂CO₃.

Observation Table:

Calculations:-

Percentage purity =V XE xAM x 100/W x RM

Where,

V = volume of HCI used (ml).
E = equivalent factor.
AM ss actual molarity.
RM = required molarity.
W = weight of sample (g).

NOTE: The equivalent factor of sodium carbonate for I ml of 1 M HCl is 0.05299.

Result:

The percentage purity of sodium carbonate was found to be

 Inorganic Chemistry Experiment No. 10

Aim:- To perform the assay of sodium bicarbonate as per I.P.

Requirements:-

Chemicals required:-Sodium bicarbonate (sample), sodium hydroxide, methyl orange indicator

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- Given sample of sodium bicarbonate is dissolved in carbon dioxide-free water and titrated against hydrochloric acid. End point can be detected by using methyl orange indicator.

Reaction involved in this titration is as follows.

Procedure:-

Preparation of reagents and solutions:-

Preparation and standardization of hydrochloric acid (1 M):-

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the HCl solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the HCl solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the HCl solution.
3. Weigh accurately about 1 .5 g of Na₂HCO₃ in a conical flask and dissolve in 50 ml of carbon dioxide-free water.
4. Add 2 drops of methyl orange indicator.
5. Then fill the burette with standardized HCl solution.
6. Start titration with the HCl until reach the endpoint. The first titration should be performed by adding 0.50 ml portions of HCl solution from burette, with swirling. The approach of the endpoint is suggested by the temporary appearance of a pink colour that fades when the solution is swirled for upto 10 seconds. A pink colour that persists for more than 30 seconds signals the actual endpoint.
   Note:- The solution may lose its colour after 30 seconds or more, but it is not considered.
7. The first titration gives a rough idea of the amount of HCl needed to neutralize the
   Na₂HCO₃.
8. Record the reading of burette.
9. Repeat the titration three times to get precise readings. For these we can add about 70% of the needed HCl quickly and then, near the end, add HCl one drop at a time until the endpoint is observed.
10. Take mean of them and calculate the percentage purity of Na₂HCO₃.

Observation Table:-

Calculations:-

Percentage purity = VxExAMx 100/W X RM

Where,
V = volume of HCl used (ml).
E = equivalent factor.
AM = actual molarity.
RM = required molarity .
W = weight of sample (g).

NOTE:- Equivalent factor of sodium bicarbonate for 1 ml of 1 M HCl is 0.08401.

Result:- The percentage purity of sodium bicarbonate was found to be

Redox Titrations

Redox titration involves the change in valency or oxidation states of reactants. Oxidation and reduction are takes place simultaneously in redox titration reaction. One substance is oxidized and other is reduced at a time.

Oxidation can be defined in following terms:-

The substance which loses electrons and get itself oxidized is called reducing agent. Some common reducing agents are antimony trioxide, ferrous sulphate, sodium thiosulphate, stannous chloride, oxalic acid etc.

Reduction can be defined in following terms:

The substance which gain electrons and get itself reduced is called oxidizing agent. Some common oxidizing agents are potassium permanganate, potassium dichromate, potassium bromate, potassium iodate etc.

Redox titrations are of following types:-

1. Permanganametry:- Titrations involving potassium permanganate.
2. Iodimetry:- Titrations involving iodine.
3. Iodometry:- Titration involving liberated iodine.
4. Chromatometry:- Titrations involving potassium dichromate.
5. Bromatometry:- Titrations involving bromine.

End point in redox titrations can be detected by using external indicator (starch paper), internal indicator (methylene blue), self indicator (potassium permanganate in permanganametry).

 Inorganic Chemistry Experiment No. 11

AIM:- To perform the assay of ferrous sulphate.

Requirements:-

Chemicals required:- Sulphuric acid, potassium permanganate, ferrous sulphate (sample).

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- Ferrous sulphate is mainly used as hematinic and is a reducing agent. Assay of ferrous sulphate is an example of redox titration (permangnametry). Potassium permanganate acts as an strong oxidizing agent in acidic medium that oxidizes divalent ferrous sulphate to trivalent ferric sulphate.

Known strength of potassium permanganate is titrated with ferrous sulphate. End point can be detected with appearance of permanent pink colour, potassium permanganate acts as self indicator. Reaction involved in this titration is as follows.

Procedure:-

Preparation of reagents and solutions:-

1. Preparation and standardization of KMnO₄ (0.1 N)
2. Dilute sulphuric acid:- Dilute 57 ml of sulphuric acid to 1000 ml with distilled water.

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the KMnO₄ solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the KMnO₄ solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the KMnO₄solution.
3. Weigh accurately about 1 g of ferrous sulphate in a conical flask and dissolve in 20 ml of dilute sulphuric acid.
4. Then till the burette with standardized KMn04 solution.
5. Start titration with the KMnO4 solution until reach the endpoint. The approach of the endpoint is suggested by the temporary appearance of a pink colour that fades when the solution is swirled for upto 10 seconds. A pink colour that persists for more than 30 seconds signals the actual endpoint.
   NOTE:-The solution may lose its colour after 30 seconds or more, but it is-not considered.
6. The first titration gives a rough idea of the amount of KMnO₄ solution needed to reach the end point.
7. Record the reading of burette.
8. Repeat the titration three times to get precise readings.
9. Take mean of them and calculate the percentage purity of ferrous sulphate.

Observation Table:-

Calculations:-

Percentage purity = V x E x AN x 100/W X RN

Where,
V = volume of KMn04 used (ml).
E = equivalent factor .
AN = actual normality of KMnO₄.
RN = required normality of KMnO₄.
W = weight of sample (g).

NOTE:- Equivalent factor of ferrous sulphate for 1 ml of 0.1 N KMnO₄ is 0.02789.

Result: The percentage purity of ferrous sulphate was found to be

 Inorganic Chemistry Experiment No. 12

Aim:- To perform the assay of ferrous ammonium sulphate (Mohr’s salt).

Requirements:-

Chemicals required:- Sulphuric acid, ferrous ammonium sulphate (sample), potassium perman ganate.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- Ferrous ammonium sulphate is also known as Mohr’s salt. Assay of ferrous ammonium sulphate is an example of redox titration (permangnametry). Potassium permanganate acts as an strong oxidizing agent in acidic medium that oxidizes divalent ferrous sulphate of mohr’s salt to trivalent ferric sulphate.

Known strength of potassium permanganate is titrated with Ferrous ammonium sulphate. End point can be detected with appearance of permanent pink
colour, potassium permanganate acts as self indicator.

Reaction involved in this titration is as follows.

Procedure:-

Preparation of reagents and solutions:-

1. Preparation and standardization of KMnO₄ (0.1N):-
2. Dilute sulphuric acid:- Dilute 57 ml of sulphuric acid to 1000 ml with distilled water.

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the KMnO₄ solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the KMnO₄ solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the KMnO₄ solution.
3. Weigh accurately about 1 g of ferrous ammonium sulphate in a conical flask and dissolve in the mixture of 20 ml distilled water and 20 ml of dilute sulphuric acid.
4. Then fill the burette with standardized KMnO₄ Solution.
5. Start titration with the KMnO₄ solution until reach the endpoint. The approach of the endpoint is suggested by the temporary appearance of a pink colour that fades when the solution is swirled for upto 10 seconds. A pink colour that persists for more than 30 seconds signals the actual endpoint.
   NOTE:- The solution may lose its colour after 30 seconds or more, but it is not considered.
6. Record the reading of burette.
7. Repeat the titration three times to get precise readings.
8. Take mean of them and calculate the percentage purity of ferrous ammonium sulphate.

Observation Table:-

Calculations:

Percentage purity = V x E x AN X 100/W x RN

Where,

V = volume of KMnO₄ used (ml).
E = equivalent factor.
AN = actual normality of KMnO₄.
RN = required normality of KMnO₄.
W= weight of sample (g).

Note:-  Equivalent factor of ferrous ammonium sulphate for 1 ml of 0.1 N KMnO₄ is 0.03921.

Result:- The percentage purity of ferrous ammonium sulphate was found to be

 Inorganic Chemistry Experiment No. 13

Aim: Perform the assay of copper sulphate.

Requirements:-

Chemicals required:- Sodium thiosulphate, potassium iodide, acetic acid, potassium thiocyanate, starch indicator, copper sulphate (sample).

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- Assay of copper sulphate is an example of iodometric titration. In the presence of acetic acid, Copper sulphate reacts with potassium iodide and give cupric iodide.

Cupric iodide decomposes into cuprous iodide and liberate free iodine due to unstability.

Known strength of sodium thiosulphate is titrated with liberated free iodine. End point can be detected by using starch as an indicator.

Decomposition of cupric iodide to cuprous iodide is reversible. Potassium thiocyanate is added towards the end of reaction to convert cuprous iodide into cuprous thiocyanate which is more sparingly soluble than cuprous iodide.

Procedure;-

Preparation of reagents and solutions:-

Preparation and standardization of Na₂S₂O₃ (0.1 N):-

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the Na₂S₂O₃ solution before you fill it up for the titration.  Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the Na₂S₂O₃ solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the Na₂S₂O₃ solution.
3. Weigh accurately about 1 g of copper sulphate in a conical flask and dissolve in 50 ml of distilled water.
4. Add 3 g of potassium iodide and 5 ml acetic acid.
5. Add 2 to 3 drops of starch indicator.
6. Then fill the burette with standardized Na₂S₂O₃ solution.
7. Start titration with the Na₂S₂O₃ solution. Continue titration until temporary appearance of a faint blue colour that fades when the solution is swirled for upto 10 seconds. Continue further untill blue colour that persists for more than 30 seconds.
8. Add 2 g of potassium thiocyanate and stirr well.
9. Continue titration untill blue colour disappears.
10. The first titration gives a rough idea of the amount of Na₂S₂O₃ solution needed.
11. Record the reading of burette.
12. Repeat the titration three times to get precise readings.
13. Take mean of them and calculate the percentage purity of copper sulphate.

OBSERVATION TABLE:-

Calculations:-

Percentage purity = V x E x AN x 100/W xRN

Where,
V= volume of Na₂S₂O₃ used (ml).
E = equivalent factor .
AN = actual normality of Na₂S₂O₃.
RN = required normality of Na₂S₂O₃.
W = weight of sample (g).

NOTE:- Equivalent factor of copper sulphate for 1 ml of 0.1 N Na₂S₂O₃ is 0.02497.

Result:- The percentage purity of copper sulphate was found to be

Complexometric Titration

Complexometric titration involves titration between metal ions and complexing agent or chelating agent (Ligand). This titration is based on the analytical application of a complexation reaction.

In this method, an ion is changed into a complex ion and the equivalence point is determined with the help of metal indicators or electrometrically. An EDTA (disodium edetate) is a popular complexing agent or chilon. The chilons react with metal ions to form a special type of complex known as chelate

 Inorganic Chemistry EXPERIMENT NO. 14

Aim: To perform the assay of magnesium sulphate as per I.P.

Requirements:-

Chemicals required:- Magnesium sulphate (sample), EDTA, mordant black ammonia, ammonium chloride.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- Magnesium sulphate is titrated directly against disodium edetate in the presence of strong ammonia-ammonium chloride solution. End point is detected by mordant black 11 mixture as an indicator.

Reaction involved in this titration is as follows.

Procedure:-

Preparation of reagents and solutions:-

1. Preparation and standardization of disodium edetate (0.05 M)
2. Strong ammonia-ammonium chloride solution:- Mix 10 ml of water with 20 ml strong ammonia solution and saturate it with ammonium chloride.

Titration:-

1. Clean and dry all glassware as per standard laboratoiy procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the disodium edetate solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the disodium edetate solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the disodium edetate solution.
3. Weigh accurately about 0.3 g of magnesium sulphate in a conical flask and dissolve in 50 ml of distilled water.
4. Add 10 ml of strong ammonia-ammonium chloride solution.
5. Add 2 drops of mordant black ll mixture as an indicator.
6. Then fill the burette with standardized disodium edetate solution.
7. Start titration with the disodium edetate until reach the endpoint. The approach of the endpoint is suggested by the change of pink colour to blue.
8. Record the reading of burette.
9. Repeat the titration three times to get precise readings.
10. Take mean of them and calculate the percentage purity of magnesium sulphate.

Observation Table:

Calculations:-

Percentage purity = V x E X AM x 100/W X RM

Where,
V = volume of disodium edetate used (ml).
E = equivalent factor.
AM = actual molarity.
RM = required molarity.
W = weight of sample (g).

Note:- Equivalent factor of magnesium sulphate for 1 ml of 0.05 M disodium edetate is 0.00602.

Result:  The percentage purity of magnesium sulphate was found to be

 Inorganic Chemistry Experiment No. 15

Aim:- To perform the assay of calcium gluconate as per I.P.

Requirements:-

Chemicals required:- Calcium gluconate (sample), EDTA, mordant black II mixture, ammonia, ammonium chloride.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- This is a replacement titration. Magnesium forms complex with mordant black ll mixture indicator which shows first colour.

Magnesium-indicator complex is much more stable than calcium-indicator complex therefore calcium has not any effect on magnesium-indicator complex. On titration against disodium edetate complex of calcium and disodium edetate is formed.

When calcium is totally consumed, next drop of disodium edetate breaks the magnesium indicator complex and make complex with magnesium by liberating free indicator. End point is detected by observing second colour at that time.

Procedure:-

Preparation of reagents and solutions:

1. Preparation and standardization of disodium edetate (0.05 M)
2. Preparation of MgSO₄ (0.05 M):- Accurately weigh about 600 mg of anhydrous magnesium sulphate and dissolve in 100 ml of distilled water.
3. Strong ammonia-ammonium chloride solution:- Mix 10 ml of water with 20 ml strong ammonia solution and saturate it with ammonium chloride.

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the disodium edetate solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the disodium edetate solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the disodium edetate solution.
3. Weigh accurately about 0.5 g of calcium gluconate in a conical flask and dissolve in 50 ml of warm water. Allow to cool.
4. Add 5 ml of 0.05 M magnesium sulphate.
5. Add 10 ml of strong ammonia-ammonium chloride solution.
6. Add 2 drops of mordant black 11 mixture as an indicator.
7. Then fill the burette with standardized disodium edetate solution.
8. Start titration with the disodium edetate until reach the endpoint. The approach of the endpoint is suggested by the change in colour.
9. Record the reading of burette (A)
10. Repeat the titration three times to get precise readings.
11. Take mean of them and calculate the percentage purity of calcium gluconate.
12. Repeat the titration again using same procedure without calcium gluconate for blank reading

Observation Table:-

Calculations:-

Percentage purity = V x E x AM x 100/W X RM

Where,
V= volume of disodium edetate used (ml).
V= A-B
A = volume of EDTA used in titration with calcium gluconate.
B = volume of EDTA used in titration without calcium gluconate.
E = equivalent factor.
AM = actual molarity.
RM = required molarity.
W = weight of sample (g).

Note: The equivalent factor of calcium gluconate for 1 ml of 0.05 M disodium edetate is 0.02242.

Result:- The percentage purity of calcium gluconate was found to be

 Inorganic Chemistry Experiment No. 16

AIM:- To perform the assay of calcium lactate as per I.P.

Requirements:-

Chemicals required:- Calcium lactate (sample), EDTA, mordant black 11 mixture, ammonia,anhydrous magnesium sulphate, ammonium chloride.

Glassware required:- Burette, pipette, conical flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- This is a replacement titration. Magnesium forms complex with mordant black 11 mixture indicator which shows first colour.

Magnesium-indicator complex is much more stable than calcium-indicator complex therefore calcium has no any effect on magnesium-indicator complex, on titration against disodium edetate complex of calcium and disodium edetate is formed.

When calcium is totally consumed, next drop of disodium edetate breaks the magnesiumindicator complex and make complex with magnesium by liberating free indicator. End point is detected by observing second colour at that time.

Procedure:

Preparation of reagents and solutionsi-

1. Preparation and standardization of disodium edetate (0.05 M)
2. Preparation of MgSO₄  (0.05 M):- Accurately weigh about 600 mg of anhydrous magnesium sulphate and dissolve in 100 ml of distilled water.
3. Strong ammonia-ammonium chloride solution:- Mix 10 ml of water with 20 ml strong ammonia solution and saturate it with ammonium chloride.

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the disodium edetate solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the disodium edetate solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the disodium edetate solution.
3. Weigh accurately about 0.3 g of calcium lactate in a conical flask and dissolve in 50ml of distilled water.
4. Add 5 ml of 0.05 M magnesium sulphate.
5. Add 10 ml of strong ammonia-ammonium chloride sloution.
6. Add 2 drops of mordant black 11 mixture as an indicator.
7. Then fill the burette with standardized disodium edetate solution.
8. Start titration with the disodium edetate until reach the endpoint. The approach of the endpoint is suggested by the change in colour.
9. Record the reading of burette (A)
10. Repeat the titration three times to get precise readings.
11. Take mean of them and calculate the percentage purity of calcium lactate.
12. Repeat the titration again using same procedure without calcium lactate for blank reading (B)

Observation Table:-

Calculations:-

Percentage purity = V x E x AM x 100/W X RM

Where,
V = volume of disodium edetate used (ml).
V= A-B
A = volume of EDTA used in titration with calcium lactate.
B = volume of EDTA used in titration without calcium lactate.
E = equivalent factor.
AM = actual molarity.
RM = required molarity’.
W = weight of sample (g).

NOTE:- Equivalent factor of calcium lactate for 1 ml of 0.05 M disodium edetate is 0.01091.

Result: The percentage purity’ of calcium lactate was found to be

Precipitation Titration

Precipitations titration involves the formation of precipitate. Silver nitrate is the most important precipitating agent The titration which uses silver nitrate as precipitating agent is also called argentometric titration.

End point in precipitation titrations can be detected by using potentiometric or amperometric methods, indicators like potassium chromate, ferric ammonium sulphate or by adsorption indicators like rhodamine dye.

Mohr’s method is commonly used method in precipitation titrations for determination of halides of sodium and potassium. This is also called direct method. Sodium or potassium halides are allowed to react with silver nitrate solution.

When all the halides are precipitated by silver nitrate by formation of silver halides, then silver nitrate reacts with potassium chromate solution to give a red precipitate i.e. end point, due to formation of silver chromate.

Volhard’s method is also commonly used to determine halide content in an acidic solution. Known amount of excess silver nitrate solution is allowed to react with halides, which results in precipitates of silver halide.

Precipitates are separated by filtration and excess unreacted silver nitrate solution is determined by titration with standard ammonium thiocyanate solution using ferric alum as indicator.

 Inorganic Chemistry Experiment No. 17

Aim:- To perform the assay of sodium chloride. (Mohr’s method)

Requirements:-

Chemicals required:- Sodium chloride (sample), potassium chromate, silver nitrate.

Glassware required:- Burette, pipette, conical flask, volumetric flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- Silver nitrate is titrated directly against sodium chloride and form white precipitate silver chloride with sodium nitrate.

When all the chlorides of sodium chloride is consumed. It reacts with potassium chromate and end point can be detected with appearance of brick red colour due to formation silver chromate along with potassium nitrate.

Procedure:-

Preparation of reagents and solutions:-

1. Preparation and standardization of silver nitrate (0.1 M)
2. Preparation of sodium chloride (sample) solution:- Weigh accurately about 1 g of sodium chloride (sample) and dissolve in 100 ml of distilled water.
3. Preparation of potassium chromate solution (5% w/v):- Weigh accurately about 5 g of potassium chromate and dissolve in 100 ml distilled water.

Titration:-

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the silver nitrate solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the silver nitrate solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the silver nitrate solution.
3. Take 10 ml of sodium chloride (sample) solution in a conical flask.
4. Add 2 to 3 drops of potassium chromate solution as an indicator.
5. Then fill the burette with standardized silver nitrate solution.
6. Start titration with the silver nitrate solution until reach the endpoint. The approach of the endpoint is suggested by the appearance of brick red colour.
7. Record the reading of burette.
8. Repeat the titration three times to get precise readings.
9. Take mean of them and calculate the percentage purity of sodium chloride.

Observation Table:-

Calculations:

Percentage purity = V x E x AM x 100/ W xRM

Where,
V = volume of silver nitrate used (ml).
E = equivalent factor.
AM = actual molarity.
RM = required molarity.
W = weight of sample (g).

NOTE:- Equivalent factor of sodium chloride for 1 ml of 0.1 M silver nitrate is 0.005845 .

Result: The percentage purity of sodium chloride was found to be

 Inorganic Chemistry Experiment No. 18

Aim:- To perform the assay of potassium chloride. (Mohr’s method)

Requirements:-

Chemicals required:- Potassium chloride (sample), potassium chromate, silver nitrate.

Glassware required:- Burette, pipette, conical flask, volumetric flask, funnel, beaker, glass rod.

Equipment required:- Weighing balance.

Principle:- Silver nitrate is titrated directly against potassium chloride and form white precipitate silver chloride with potassium nitrate.

When all the chloride of potassium chloride is consumed. It reacts with potassium chromate and end point can be detected with appearance of brick red colour due to formation silver chromate along with potassium nitrate.

Procedure:

Preparation of reagents and solutions:-‘

1. Preparation and standardization of silver nitrate (0.1 M):-
2. Preparation of potassium chloride (sample) solution:- Weigh accurately about 1 g of potassium chloride (sample) and dissolve in 100 ml of distilled water.
3. Preparation of potassium chromate solution (5% w/v):- Weigh accurately about 5 g of potassium chromate and dissolve in 100 ml distilled water.

Titration:

1. Clean and dry all glassware as per standard laboratory procedure.
2. Rinse the burette with distilled water. Then, pre-rinse it with a portion of the silver nitrate solution before you fill it up for the titration. Pre-rinsing is necessary to ensure that all of the solution in the burette is the desired solution, not a diluted or contaminated solution.
   To do this, add about 10 ml of the silver nitrate solution to the clean burette. Carefully turn the burette on its side so the liquid slowly runs out the top. Rotate the burette on its axis during this time to make sure the solution wets the sides all the way to the top. Pour the rinse from the burette into a waste beaker. Repeat the rinsing process with a second portion of the , silver nitrate solution.
3. Take 10 ml of potassium chloride (sample) solution in a conical flask.
4. Add 2 to 3 drops of potassium chromate solution as an indicator.
5. Then fill the burette with standardized silver nitrate solution.
6. Start titration with the silver nitrate solution until reach the endpoint. The approach of the endpoint is suggested by the appearance of brick red colour.
7. Record the reading of burette.
8. Repeat the titration three times to get precise readings.
9. Take mean of them and calculate the percentage purity of potassium chloride.

Observation Table:-

Calculations:-

Percentage purity = V x E x AM x 100/ W xRM

Where,
V = volume of silver nitrate used (ml).
E = equivalent factor.
AM = actual molarity.
RM = required molarity.
W = weight of sample (g).

NOTE:- Equivalent factor of potassium chloride for 1 ml of 0.1 M silver nitrate is 0.007455.

Result:- The percentage purity of potassium chloride was found to be :

Non-Aqueous Titration

Non-aqueous titration involves the use of non aqueous solvents in it. Non-aqeous titrations are method of choice when reactants or products are insoluble in water, react with water or too weak acids or bases that cannot be titrated in water due to its levelling effect.

Commonly used solvents in non aqueous titrations are acetone, glacial acetic acid, formic acid, ethylene diamine, acetic anhydride and chloroform etc. End point can be detected by the indicators like crystal violet (0.5% in glacial acetic acid) and quinaldine red (0.1% in methanol) and by potentiometric methods.

Section D

Limit Test

Limit test is defined as quantitative or semiquantitative test designed to identify and control small quantity of impurity which is likely to be present in the substance. Limit test is generally carried out to determine the inorganic impurities present in the compound.

Limit test for chlorides, sulphates, iron, lead and heavy metal are carried out in Nessler cylinders. Nesseler cylinders are made up of borosilicate glass that is colourless.

It has the fixed diameter, length as per according to the Indian Pharmacopeia. Two similar kind of cylinders are required each time i.e. one for the ‘Test’ sample and other for the ‘standard’ to make comparison in the identical manner.

The quantities of the sample vary according to the limits of impurities while the standard remains constant. No numerical values for ths limits in these tests are prescribed in the pharmacopoeias, as it is not practicable.

Generally an aqueous solution of the substance is prepared. Sometimes a solution of the substance is prepared by dissolving in an acid or if the solution is alkaline it is neutralized with nitric or hydrochloric acid as specific in the monograph of the pharmacopoeia.

The extent of opalescence, turbidity and colour is affected by other impurities present in the substance.

 Inorganic Chemistry Experiment No. 19

AIM:- To perform the limit test for chlorides in the given sample (magnesium sulphate).

Requirements:–

Chemicals required:- Sodium chloride, silver nitrate, sample (magnesium sulphate), dilute nitric
acid.

Glassware required:- Pair of Nessler cylinder, volumetric flask, beaker, measuring cylinder,glass rod, spatula, pipette.

Equipment required:- Weighing balance.

Principle:- This test is based on reaction between chloride ion and silver nitrate in the presence of nitric acid. It is an argentometric titration reaction. In this reaction chlorides are precipitated silver chloride.

When a small quantity of chloride ion is present in solution silver chloride shows opalescence while in large amount it precipitates. Opalescence of test sample is compared with standard in limit test for chlorides.

Procedure:-

Preparation of reagents and solutions:

1. Chloride standard solution (25 ppm chlorides):- Take 5 ml of 0.0824 % w/v solution of NaCl in 100 ml volumetric flask and make upto the mark with distilled water.
2. Silver nitrate solution (0.1 M):- Dissolve 1.69 g of silver nitrate in 60 ml distilled water in 100 ml volumetric flask and make upto 100 ml with distilled water.

Preparation of test solution:-

1. Weigh accurately about 1 g of magnesium sulphate or sample .
2. Dissolve it in 10 ml of distilled water.
3. Transfer the solution in Nessler cylinder and label it as “Test “.
4. Add 10 ml dilute nitric acid.
5. Make upto 50 ml mark with distilled water.
6. Now add 1 ml 0.1 M silver nitrate solution in it.
7. Stir with the glass rod and set aside for 5 minutes.

Preparation of standard solutions

1. Add 10 ml standard chloride solution in Nessler cylinder and label it as “Standard “.
2. Make upto 50 ml mark with distilled water.
3. Now add 1 ml 0. 1 M silver nitrate solution in it.
4. Stir with the glass rod and set aside for 5 minutes.

Observation:- Compare the opalescence of both test and standard solutions and write the observalion as follows:-

1. If Test solution shows more opalescence than standard-limit test fails.
2. If Test solution shows less opalescence than standard-limit test pass.

NOTE:- Compare these solutions in dark background i.e. black to get good contrast for comparison of the solutions.

Result:- Civen sample of magnesium sulphate pass / fails the limit test for chlorides.

 Inorganic Chemistry Experiment No. 20

Aim:- To perform the limit test for sulphates in given sample (sodium bicarbonate).

Requirements:

Chemicals required:- Sample (sodium bicarbonate), barium chloride, acetic acid, potassium sulphate.

Glassware required:- pair 0f Nessler cylinder, volumetric flask, beaker, measuring cylinder,glass rod, spatula, pipette.

Equipment required:- Weighing balance.

Principle: When sulphates interacts with barium chloride in the presence of acetic acid,sulphates precipitate as barium sulphate. When a small quantity of sulphates are present in solution, barium sulphate shows opalescence. The opalescence of test sample is compared with standard in limit test for sulphates.

To prevent the precipitation of other anions like phosphate, oxalate, borate etc with solution of barium chloride (which can affects the results), acetic acid is added. Therefore, in the presence of acetic acid, only sulphates are precipitated.

Procedure:-

Preparation of reagents and solutions:*

1. Barium chloride solution (25 % w/v):- Dissolve 25 g of barium chloride in 100 ml distilled water stir well with glass rod .
2. Ethanolic sulphate standard solution (10 ppm SO4-):- Take 1ml of 0.181% w/v solution of potassium sulphate in ethanol (30%) in 100 ml volumetric flask and make upto 100 ml with ethanol (30%).
3. Sulphate standard solution (10 ppm SO4-):- Take
   potassium sulphate in distilled water in 100 ml volumetric flask and make upto 100 ml with distilled water.
4. Sodium bicarbonate solution:- Dissolve 1.0 g of sodium bicarbonate in 1 ml of distilled water, then neutralize it with hydrochloric acid and dilute upto 15 ml with distilled water.

Preparation of test solution:-

1. 1. Take lml barium chloride solution (25 % w/v) in Nessler cylinder.
2.  Now add 1.5 ml of ethanolic sulphate standard solution (10 ppm SO^2-₄“) in it.
3. Mix well and allow to stand it for 1 minute.
4. Add 15 ml solution of sodium bicarbonate in it.
5. Add 0.15 ml of 5 M Acetic acid.
6. Make upto 50 ml with distilled water.
7. Stir with the glass rod and set aside for 5 minutes.

Preparation of Standard solution:-

1. Take 1 ml Barium chloride solution (25 % w/v) in Nessler cylinder.
2. Now add 1.5 ml of ethanolic sulphate standard solution (10 ppm SO^2-₄) in it.
3. Mix well and allow to stand it for 1 minute.
4. Add 15 ml sulphate standard solution (10 ppm SO^2-₄) in it.
5. Add 0.15 ml of 5 M acetic acid.
6. Make upto 50 ml with distilled water.
7. Stir with the glass rod and set aside for 5 minutes.

Observation:- Compare the opalescence of both test and standard solutions and write the observation as foliows:-

1. If test solution shows more opalescence than standard – limit test fails.
2. If test solution shows less opalescence than standard – limit test pass.

NOTE:- Compare these solutions in dark background i.e. black to get good contrast for comparison of the solutions.

Result:- Given sample of sodium chloride pass/fails the limit test for sulphates.

 Inorganic Chemistry Experiment No. 21

Aim: To perform the limit text for iron of given sample (sodium chloride).

Requirements:

Chemicals required:- Sample (sodium chloride), iron free citric acid solution (20% w/v) iron free ammonia solution, feme ammonium sulphate, thioglycollic acid, sulphuric acid.

Glassware required:- Pair of Ncsslcr cylinder, volumetric flask, beaker, measuring cylinder, glass rod, spatula, pipette.

Equipment required – Weighing balance.

Other requirements – pH paper.

Principle:- When iron interacts with thioglycollic acid in the presence of citric acid and the ammoniacal alkaline medium, ferrous salt of thioglycollic acid is produced which gives purple colour.

Colour intensity of lest sample is compared w ith standard in limit test for iron. To prevent the precipitation of iron with ammonia as iron hydroxides, citric acid is added. This keeps iron in solution form in the presence of ammonia.

NOTE:- Reagents used in this test must be completely free from iron otherwise false results will obtained.

Procedure:

Preparation of reagents and solutions:

1. Sodium chloride or sample, distilled water, iron free citric acid solution (20% w/v), iron free ammonia solution, thioglycollic acid.
2. Iron standard solution (20 ppm Fe):- Take 1 ml of 0.1726 % w/v solution ferric ammonium sulphate in 0.05 M sulphuric acid make upto 10 ml with distilled water.

Preparation of test solution:-

1. Weigh accurately about I g of sodium chloride or sample.
2. Dissolve it in 40 ml of distilled water.
3. Transfer the solution made in step 2 in Nessler cylinder and label it as “Test “.
4. Add 2 ml iron free citric acid solution (20% w/v).
5. Now add 0. 1 ml thioglycollic acid in it .
6. Alkaline the solution with iron free ammonia solution.
7. Dilute the solution upto 50 ml with distilled water.
8. Stir with the glass rod and set aside for 5 minutes.

Preparation of Standard solution:-

1. Add 2 ml iron standard solution (20 ppm Fe) in Nessler cylinder and label it as “Standard .
2. Make upto 40 ml mark with distilled water.
3. Add 2 ml iron free citric acid solution (20% w/v).
4. Now add 0.1 ml thioglycollic acid in it.
5. Alkaline the solution with iron free ammonia solution.
6. Dilute the solution upto 50 ml with distilled water.
7. Stir with the glass rod and set aside for 5 minutes.

OBSERVATION:- Compare the colour of both test and standard solutions and write the observation as follows:-

1. If test solution shows more colour than standard – limit test fails.
2. If test solution shows less colour than standard – limit test pass.

Results- Given sample of sodium chloride pass/fails the limit test for iron.

 Inorganic Chemistry Experiment No. 22

Aim:- To perform the limit test for heavy metais in given sample (sodium chloride).

Requirements:-

Chemicals required:- Sample (sodium chloride), hydrochloric acid, sulphuric acid, ammonia solution, saturated hydrogen sulphide solution, lead nitrate, nitric acid.

Glassware required:- pair 0f Nessler cylinder, volumetric flask, beaker, measuring cylinder, glass rod, spatula, pipette.

Equipment required:- Weighing balance.

Other requirements:- pH paper.

Principle: When hydrogen sulphide reacts with heavy metals (i.e. lead, antimony, bismuth ,tin, cobalt, manganese) in the presence of acidic medium, it produces metal sulphides.

These metal sulphides are distributed in colloidal state and produce brownish colour. Colour intensity of test sample is compared with standard in limit test for heavy metals.

NOTE:- Heavy metals like lead, antimony, bismuth, tin, cobalt, manganese are grouped together for their limit test in Indian. Pharmacopoeia and their quantity is expressed in the terms of lead.

PROCEDURE:-

Preparation of reagents and solutions

1. Standard lead solution (20ppm):- Weigh accurately about 400 mg of lead nitrate in distilled water containing 2 ml of nitric acid and dilute upto 250 ml. Take 10 ml of this solution and dilute upto 100 ml. Further take 10 ml of this solution and dilute upto 50 ml with distilled water.
2.  Dilute acetic acid:- Dilute 57 ml of glacial acetic acid to 1000 ml with distilled water.

For Colourless Substances:-

Preparation of test solution:-

1. Take 25 ml solution of test sample in Nessler cylinder and label it as “Test
   NOTE:- Prepare solution of test sample as directed in pharmacopoeia or otherwise dissolve specified quantity of test sample in 25 ml distilled water.
2. Adjust the pH of solution between 3.0 to 4.0 with dilute acetic acid.
3. Dilute upto 35 ml with distilled water.
4. Mix well with glass rod.
5. Now add 10 ml of freshly prepared saturated solution of hydrogen sulphide.
6. Make the volume upto 50 ml with distilled water.
7. Stir with the glass rod and set aside for 5 minutes.

Preparation of standard solution:-

1. Take 2 ml standard lead solution (20 ppm) in Nessler cylinder and label it as “Standard “.
2. Make upto 2 ml with distilled water.
3. Adjust the pH of solution between 3.0 to 4.0 with dilute acetic acid.
4. Dilute upto 35 ml with distilled water.
5. Mix well with glass rod.
6. Now add 10 ml of freshly prepared saturated solution of hydrogen sulphide.
7. Make the volume upto 50 ml with distilled water.
8. Stir with the glass rod and set aside for 5 minutes.

For Coloured Substances

Preparation of test solution:-

1. Accurately weigh a quantity of substance as directed in pharmacopoeia or otherwise weigh specified quantity of sustance in a crucible.
2. Wet it by sufficient quantity of sulphuric acid
3. Ignite at low temperture until thoroughly charred.
4. Add 2 ml nitric acid in charred mass and 5 drops of sulphuric acid.
5. Heat until, white fumes no longer evolved from it.
6. Ignite it, until carbon is completey burnt off at 500 to 600 °C.
7. Allow to cool and add 4 ml hydrochloric acid in it.
8. Digest it on water bath for about 15 minutes and evaporate to dryness.
9. Add 1 drop of hydrochloric acid to moisten the residue.
10. Now add 10 ml hot water and digest for 2 minutes.
11. Alkaline the solution with dropwise addition of ammonia solution (just alkaline to the litmus paper).
12. Make upto 25 ml with distilled water.
13. Adjust the pH of solution between 3.0 to 4.0 with dilute acetic acid.
14. Dilute upto 35 ml with distilled water.
15. Mix well with glass rod .
16. Now add 10 ml of freshly prepared saturated solution of hydrogen sulphide.’
17. Make the volume upto 50 ml with distilled water.
18. Stir with the glass rod and set aside for 5 minutes.

Preparation of Standard solution:-

Procedure same as Preparation of standard solution for colourless substances.

Observation:- Compare the colour of both test and standard solutions and observation as follows:-

1. If test solution shows more colour than standard – limit test fails.
2. If test solution shows less colour than standard – limit test pass.

Result: Given sample Of sodium chloride pass/ fails thnimit ttst for heavy metal (lead, antimony, bismuth, tin, cobalt, manganese).

 Inorganic Chemistry Experiment No. 23

Aim:- To perform (he limit test for arsenic in given sample (ammonium chloride).

Requirements:-

Chemicals required:- Sample (ammonium chloride), granulated zinc, potassium iodide, arsenic trioxide, sodium hydroxide, stannous chloride solution.

Glassware required:- Volumetric flask, beaker, measuring cylinde, glass rod, spatula, pipette.

Equipment required:- jwo sets of arsenic test apparatus, weighing balance.

Other requirements:- Cotton, mercuric chloride paper.

Principle:- when sample containing arsenic is dissolved in acid, arsenic impurity get converted into arsenious acid (trivalent) or arsenic acid (pentavalent) depending upon the valency state of arsenic present in sample.

On treatment with stannous chloride (reducing agent) pentavalent arsenic acid is converted into trivalent arsenious acid.

NOTE:- Potassium iodide is used in test because it facilitate the conversion of pentavalent arsenic acid into trivalent arsenious acid.

On treatment with stannous chloride (reducing agent) pentavalent arsenic acid is converted into trivalent arsenious acid.

With the help of nascent hydrogen produced by Zn + HCl, arsenious acid is converted into arsine gas (gaseous arsenious hydride)

Produced arsine gas is carried out through the tube by passing through mercuric chloride paper .When arsenic gas reacts with mercuric chloride, brown or yellow stain is produced on mercuric chloride paper. Intensity of colour produced is proportional to the quantity of arsenic present.

Similarly,, stain is produced for standard solution of arsenic and intensity of two stains is compared and results are noted down.

NOTE:- Reagents used in this test must be completely free or low in arsenic otherwise false results will obtained. They are commercially available.

Arsenic test apparatus: A wide-mouth Slass bottle which is fitted with a rubber bung and a glass tube with 200 mm length with internal diameter 6.5 mm and outer diameter 8.0 mm is passes through it.

Upper end of this tube is open and lower end is tapered by reducing diameter to l (diameter of glass tube is reduced at lower end for slow and smooth passage of arsine gas ).

At the side of lower end, a hole of 2 mm diameter is made from where the lower end starts tapering (this hole is made for the alternate passage for arsine gas if water condenses at lower end ).

Cotton wool moistened with lead acetate solution, dried and packed in glass tube. Lead cotton trap hydrogen sulphide gas if any, which can interfere with the test by giving stain on mercuric chloride paper.

Upper end of tube is fitted with two rubber bungs and act like tube of 6.5 mm diameter with the help of clips enclosing flat mercuric chloride paper in it.

Procedure:-

Preparation of reagents and solutions:-

1. Arsenic standard solution (10 ppm As):- Weigh accurately 0.330 g of arsenic trioxide and dissolve it in 5 ml of 2 M sodium hydroxide solution, dilute upto 250 ml with distilled water. Take 1ml of this solution and make upto 100 ml with distilled water.
2. Stannated hydrochloric acid:- Add 1 ml of stannous chloride solution and make upto 100 ml with hydrochloric acid.

Preparation of test solution:-

1. Add 50 ml distilled water in arsenic test apparatus bottle label this apparatus as “Test
2. Weigh accurately and dissolve 2.5 g of ammonium chloride sample in it.
3. Now add 10 ml stannated hydrochloric acid.
4. Add 5 ml solution of 1 M potassium iodide.
5. Now add 10 g of granulated zinc.
6. Quickly place prepared glass lube at its position and allow to stand for 40 minutes.

Preparation of standard solutions-

1. Add 50 ml distilled water in arsenic test apparatus bottle and label tills apparatus as Standard .
2. Now add and mix 1 ml of arsenic standard solution (10 ppm As) in it.
3. After mixing of step 2, add 10 ml stannated hydrochloric acid.
4. Add 5 ml solution of I M potassium iodide.
5. Now add 10 g of granulated zinc.
6. Quickly place prepared glass tube at its position and allow to stand for 40 minutes.

Observation:- Compare the yellow stain of both test and standard solutions and write the observation as follows:-

1. If test solution show yellow stain with more intensity than standard – limit test fails.
2. If test solution show yellow stain with less intensity than standard – limit test pass.

Result:- Given sample of ammonium chloride pass/fails the limit test for arsenic.

 Inorganic Chemistry Experiment No. 24

Aim:- To perform modified limit test for chloride.

Requirements:-

Chemicals required:- Sodium benzoate, sodium salicylate, crystal violet, hypophosphorus acid

Glassware required:- Ncsslcr cylinder, measuring cylinder, glass road, beaker.

Procedure:

A specified amount of the substance is dissolved in distilled water, and the volume made up to 50 ml in a Nessler cylinder. Depending upon the nature of the substance, some modifications have to be adopted for the preparation of the solution.

1. Alkaline substances have to be dissolved in acid so that effervescence ceases and much of the free acid is left in the solution as is prescribed in the test.
2. Insoluble substances are generally extracted with water and then filtered, and the filtrate is used for the test, because the presence of insoluble substance modifies the opalescence and colour.
3. Salts of organic acids like sodium benzoate, sodium, salicylate, etc. liberate free water insoluble organic acid during acidification which is filtered off and the filtrate is employed for the test.
4. Coloured substances like crystal violet, malachite green, etc. are carbonised and the ash so produced is extracted in water.
5. Deeply coloured substances have to be decolourised before test e.g., potassium permanganate is reduced by boiling with alcohol and the filtrate is used.
6. Reducing substances like hypophosphorus acid, which react with silver nitrate in the limit test for chlorides should be oxidized with nitric acid or some other oxidizing agents before carrying out the test.

 Inorganic Chemistry Experiment No. 25

Aim:- To perform modified limit test for sulphate.

Requirements:-

Chemicals required:- Sodium benzoate, sodium salicylate, crystal violet, hypophosphorus acid

Glassware required:- Nessler cylinder, measuring cylinder, glass road, beaker.

Procedure:

A specified amount of the substance is dissolved in distilled water, and the volume made up to 50 ml in a Nessler cylinder. Depending upon the nature of the substance, some modifications have to be adopted for the preparation of the solution.

1. Alkaline substances have to be dissolved in acid so that effervescence ceases and much of the free acid is left in the solution as is prescribed in the test.
2. Insoluble substances are generally extracted with water and then filtered, and the filtrate is used for the test, because the presence of insoluble substance modifies the opalescence and colour.
3. Salts of organic acids like sodium benzoate, sodium salicylate, etc. liberate free water insoluble organic acid during acidification which is filtered off and the filtrate is employed for the test.
4. Coloured substances like crystal violet, malachite green, etc. are carbonised and the ash so produced is extracted in water.
5. Deeply coloured substances have to be decolourised before test e.g., boiling with alcohol reduces potassium permanganate and the filtrate is used.
6. Reducing substances like hypophosphorus acid, which react with silver nitrate in the limit test for chlorides should be oxidized with nitric acid or some other oxidizing agents before carrying out the test.

Section E

Identification Test

Identification tests are performed to determine the qualitative characteristics of material under examination. For the identification of inorganic drugs and pharmaceutical aids the tests are generally based on reactions of an anion and cation present in a molecule.

Identification Tests:

Aim: Identification tests are performed for the ferrous sulphate

Tests for Ferrous Salts:

Dissolve a quantity of the substance being examined equivalent to about 1 0 mg of iron in 1 ml of water or use 1 ml of prescribed solution. Add 1 ml dilute H2SO₄and 0.1% w/v solution of 1,10-phenanthroline (1ml), an intense red colour is produced, which is discharged by addition of 0.1 M cerric ammonium sulphate is produced.

To a 1 ml solution containing net less than 1 mg of iron, add 1 ml potassium ferricyanide solution, a dark blue precipitate is formed that is insoluble in dilute HCl and is decomposed by sodium hydroxide solution.

To a 1 ml of solution containing not less than 1 mg of iron add 1 ml potassium ferrocyanide solution, a white precipitate is formed which is rapidly become blue and us insoluble in dilute HCl.

Tests for Sulphate:

Dissolve about 50 mg of the substance being examined in 5 ml of water or use 5 ml of prescribed solution. Add 1 ml of dilute HCl and 1 ml of barium chloride solution; a white precipitate is formed.

Add 0.1 ml of iodine solution to the suspension obtained in the test (1); the suspension remains yellow but is decolorised by adding stannous chloride solution drop wise. Boil the mixture; no coloured precipitate appears.

Dissolve the 50 mg Of substance being examined in 5 ml of water and add 2 ml of lead acetate solution; a white precipitate is formed which is soluble in ammonium acetate solution and in sodium hydroxide solution is produced .

Aim: Identification test for sodium bicarbonate

Tests for Sodium:

Dissolve 0.1 gm of the substance being examined in water and add 2ml of 15% w/v solution of potassium carbonate; heat to boiling; no precipitated is produced.

Add freshly prepared 4ml potassium antimonate solution and heat to boiling. Allow to cool in ice and if necessary scratch the inside of the test tube with help of glass rod; a dense, white precipitate is produced.

Acidify a solution of the substance being examined with IMacetic acid and add excess of magnesium uranyl acetate solution, a crystalline, yellow precipitate is formed.

Tests for Bicarbonate

Solutions of bicarbonate, when boiled, liberate CO₂

Treat a solution of the substance being examined with a solution of magnesium sulphate; no precipitated is produced. Boil, white precipitate is formed.

Introduce into a test tube the 0.1 gm of the substance being examined suspended in 2 ml of water.

Add 2ml of 2M acetic acid, close the test tube immediately using a stopper fitted with a glass tube bent at two right angles, heat gently and collect the gas in 5 ml barium hydroxide solution; a white precipitate is produced that dissolve on addition of an excess of dilute HCl solution.

Aim: Identification test Calcium gluconate

Tests for Gluconic Acid:

To a solution of 3% w/v calcium gluconate (1 ml), add few drops of ferric chloride solution, a yellow colour appears.
Gluconic acid is an a-hydroxy acid. It reacts with ferric chloride to form a yellow floured complex.

To the sample (0.75 gm) in warm water (7.5 ml), add glacial acetic acid (1 ml) and freshly distilled phenylhydrazine (1.5 ml). Heat the mixture on a water bath for half an hour and allow to cool.

Scratch the inner surface of the tube with a glass rod until crystals of gluconic acid phenylhydrazine begin to form. Keep the test for 10 minutes, filter,dissolve the precipitate in hot water (10 ml), add small amount of decolourising charcoal and filter.

Allow to cool and scratch the test tube to recover the white crystals which melt at about 200°C with decomposition. Phenylhydrazine forms gluconic acid phenylhydrazine with gluconic acid which is purified by boiling with chalcoal and identified on the basis of melting point determination.

Tests for calcium Ion:

Dissolve 20 mg of substance being examined in 5M acetic acid (5ml) or add 1 ml glacial acetic.acid. Add 0.5 ml potassium ferrocyanide solution, the solution remains clear. Add 50 mg. ammonium chloride; a crystalline, white precipitate is produced.

To a 0.4 % w/v solution of the substance (5 ml) add 0.2 ml of 2% w/v solution of ammonium oxalate; a white precipitate is obtained that is only sparingly soluble in dilute acetic acid but is insoluble in hydrochloric acid.

Dissolve 20 m of the substance being examined in the minimum quantity of dilute HCl and neutralize with dilute NaOH solution.

Add 5ml ammonium’carbonate solution, a white precipitate is formed which after boiling and cooling is only sparingly soluble in ammonium chloride solution.

 Inorganic Chemistry Experiment No. 26

Aim:- Identification test are performed for magnesium hydroxide.

Requirements:

Chemicals required:- Ammonium chloride, disodium hydrogen phosphate, amrponium hydroxide.

Test for Magnesium Salt:

15 gm of substance is dissolved in 2 ml of water and added 1ml of dilute ammonia solution to it; a white precipitate forms that is redissolved by adding 1ml of 2M ammonium chloride.

1 ml of 0.25 M disodium hydrogen phosphate is added; a white crystalline precipitate forms.

Ammonium chloride prevents precipitation by a common ion effect, it prevents precipitation of magnesium hydroxide due to suppression of dissociation of ammonium hydroxide.

Test for Hydroxide ion

Alkaline solution tests. When mixed with an ammonium salt and heated gently it produces an alkaline gas (fumes turn universal indicator paper blue)

 Inorganic Chemistry Experiment No. 27

Aim:- To perform the identification test for copper sulphate.

Requirements:-

Chemicals required:-Hyrochloric acid, potassium ferrocyanide TS, ammonium hydroxide.

Test for Copper Salt

Solution of cupric compounds, acidified with HCl, deposit a red film of metallic copper upon a bright, untarnished surface of metallic ion. Added an excess of 6N ammonium hydroxide to a solution of cupric salt, produce first a bluish precipitate than a deep blue coloured solution.

Solution of cupric salts yield a reddish-brown precipitate with potassium ferrocyanide TS, insoluble in dilute acid.

Tests For Purity

 Inorganic Chemistry Experiment No. 28

Aim:-To perform the swelling index of bentonite.

Requirement:-

Chemicals required:-Bentonite, Sodium Lauryl sulphate.

Apparatus required:- Beaker, glass rod, watch-glass, measuring cylinder.

Theory:-

It is a colloidal hydrated aluminum silicate which occurs naturally. The swell index is used to determine the general characteristics of bentonite. When water is added to the bentonite,each particle of it is surrounded by a layer of water.

This causes the swelling of particles and become several times larger than the original particle.

Procedure:-

1. Dissolve1 gm of sodium lauryl sulphate in 100 ml of water and transfer it to a 100 ml of measuring cylinder.
2. Weigh accurately 2 gm of bentonite and add it in into the above solution in small quantities after every 2 minutes. Allow each portion to settle.
3. Set it aside for 24 hours
4. Find out the apparent volume of the sediment at the bottom of the cylinder.

Observation:- The observation is one of the two given below:-

The apparent volume of the sediment the bottom is 24 ml or more.
The apparent volume of the sediment is less than 24 ml.

Result:- The report may be one of the two given below:-

1. The sample passes the test
2. The sample doesn’t pass the test.

Applications:-

1. It is used as a bulk laxative and also used as a base for many dermatological formulas.
2. It is an important ingredient of calamine lotion which is used as a protective.
3. It is a good pharmaceutical aid and is used as a protective colloid to stabilize emulsions.
4. It finds use as an emulisifier for oil in water emulsion.

 Inorganic Chemistry Experiment No. 29

Aim:- Acid-Neutralizing Capacity of Aluminum hydroxide Gel.

Requirements:-

Chemicals Required:-Aluminium hydroxide, hydrochloric acid

Apparatus Required:- 250 ml beaker, spatula; measuring cylinder

Theory:-AlUminum hydroxide reacts with hydrochloric acid to form aluminum chloride.

This means that aluminum hydroxide can act as a good antacid and will be able to neutralize the acid in the stomach.

Procedure:-

Add 5 gni. of tire sample into 100 ml of water in a beaker. Place the beaker in a thermostatic water bath and adjust to get 37°C in the suspension in the beaker. Add 100 ml of 0.1M hydrochloric acid, previously heated to 37°C.

Stir continuously maintaining the temperature at 37°C. Measure the pH of the solution at 37°C with the help of a pH meter after10, 15 and 20 minutes and record the same.

The pH should be more than 1.8 after 10 minutes, 2.3 after 15 minutes and 3 after 20 minutes.The pH at any time shouldn’t more than 4.5. Add 10 ml of 0.5 M hydrochloric acid, previously heated to 37 °C.

Stir continuously for one hour maintaining the temperature at 37 °C. Titrate with 0.1 M sodium hydroxide. This is a potentiometric titration. So nitrate till a pH of 3.5 is obtained.

Result:- Based on the above observation, one of the two reports may be submitted.

The sample passes the test.
Or
The sample doesn’t pass the test.

 Inorganic Chemistry Experiment No. 30

Aim:- To check the presence of iodate in potassium iodide.

Requirement:-

Chemical required:-

Theory:-The presence of iodate in potassium iodide can be done by adding dilute sulphuric acid and starch solution to an aqueous solution of the sample.

There should be no color produced. If, there is iodate, it reacts with potassium iodide in the presence of acid and liberates iodine. This will produce blue color with starch.

Procedure:-

1. Weigh1 gm. of the sample accurately in 20 ml of carbon-dioxide-free water.
2. Add 0.3 ml of dilute sulphuric acid from a 1ml graduated pipette and one drop of iodide-free starch solution.

Observation:- one of the two observation should be there.

1. No blue color is produced within 2 minutes
2. Blue color is produced within 2 minutes.

Result:-

One of the two results may be reported.

1. The sample passes the test
2. The sample doesn’t passes the test.

Preparation Of Inorganic Pharmaceutical Preparations

 Inorganic Chemistry Experiment No. 31

AIM To prepare a pure sample of Potash Alum Crystal (Fit Kari),[K₂SO₄.Al₂(SO₄)₃.24H₂0].

Requirement:-

Chemicals required:-Potassium sulphate, aluminum sulphate

Apparatus required:- Two beakers, china dish, funnel, funnel-stand, wash bottle, tripod stand and wire gauze

Theory:-Potash alum is prepared by dissolving an equimolar mixture of hydrated aluminum sulphate and potassium sulphate in minimum amount of water containing a little of sulphuric acid and then subjecting the resulting solution to crystallization, when octahedral crystal of potash alum separate out.

Procedure:-

1. Take a 250 ml beaker. Wash it with water and transfer 2.5 gm. of potassium sulfate crystals to it. Add to about 20 ml of water.Stirr to dissolve the crystals. Warm if required.
2. Take the other 250 ml beaker, wash it with water and transfer 10 gm aluminum sulphate crystals to it. Add about 20 ml of water and 1ml of dilute sulphuric acid to prevent hydrolysis of aluminum sulphate. Heat for about 5 minutes. If milkness still persists, filter the solution.
3. Mix the two solutions in a china-dish and place the china-dish on wire gauze placed over a burner. Stir the solution with a glass-rod. Concentrate the solution till the crystallization point is reached. Place the dish over a beaker containing cold water.
4. Soon the crystals of potash alum separate out. Decant off the mother liquor and wash the crystals with a small quantity of ice-cold water.
5. Dry the crystals by placing them in between the filter papers.

Observation:

Weight of crystals obtained.

Expected yield.

Colour of the crystals.

Shape of the crystals.

Applications

1. Potash Alum is used in water purification, leather tanning, and fireproof textiles.
2. It also has cosmetic uses as a deodorant, as an aftershave treatment.

Precautions

1. Cool the solution slowly to get good crystals. Donot disturb the solution while it is octahedral in shap

 Inorganic Chemistry Experiment No. 32

Aim:- To prepare and submit Boric acid.

Requirement:-

Chemicals Required: borax, cone, sulphuric acid

Apparatus Required:-beaker, glass-rod, filter paper, spatula.

Theory:- boric acid occurs naturally in volcanic jets of steam. The crude boric acid crystallizes on cooling.Commerically, boric acid is prepared from sodium borate.

Boric acid is prepared by treating borax with nitric acid. Nitric acid is preferred to hydrochloric acid because sodium nitrate is more readily soluble than sodium chloride.

Boric acid is purified by re-dissolving the washed crystals in 200 ml of boiling distilled water.

Procedure:-

1. Add 20 gm. of borax in 100ml of distilled water. Heat if necessary, to dissolve.
2. Slowly add 1M of sulphuric acid(5% H2SO4) while stirring. After each addition, test the reaction mixture with pH paper.When the paper shows a strong red color, indicating excess acid, the reaction should be complete.
3. Wash the precipitate on the filter with water till the filtrate is free from sulphate.
4. Dry the precipitate in between the folds of filter paper.

Applications;- .

1. It can be used as a local anti-infective agent.
2. It can be used as a vehicle for ophthalmic solutions.
3. It can be used as a buffer.

Result:- The crude boric acid obtained,

Inorganic Chemistry Experiment No. 33

Aim:- To prepare Ferrous sulphate from iron.

Requirement:-

Chemicals Required:- iron filings, cone. Sulphuric acid

Apparatus Required:- beaker, spatula, measuring cylinder, funnel.

Theory:-Ferrous sulphate (FeSO₄.7H₂O) traditionally known as green vitriol or copperas, forms beautiful blue green crystals of the monoclinic system. It is prepared by dissolving iron in excess of dilute Sulphuric acid.

Fe + H₂SO₄———————–FeSO₄

Procedure: It is obtained by dissolving 1 gm. of iron filling in 20 ml of dilute sulphuric acid. After the effervescence ceases, the liquid if filtered, concentrated and cooled. The green crystals formed are separated by filtration at room temperature.

Applications:-

1. It is useful in chemistry as a reducing agent and a source of ferrous ions.
2. It can also be used as a hemanitic i.e. for promoting the formation of haemoglobin in anemias caused due to iron deficiency.
3. Ferrous sulphate is used to purify wastes by flocculation