Identification tests for anions and cations, Pharmaceutical Chemistry Practical
Limit test Chlorides, Sulphate, Iron, Heavy metals * Identification tests for Anions and Cations * Prep. & std Sodium Hydroxide, Potassium Permanganate * Assay Ferrous sulphate, Calcium gluconate, Sodium chloride, Ascorbic acid, Ibuprofen * Determination of Melting point & Boiling point * Preparation Benzoic acid from Benzamide, Picric acid from Phenol * Identification & purity test Aspirin, Caffeine
Aim:
Identification tests for anions and cations as per Indian Pharmacopoeia
Cations
Apparatus:
Boiling tube Test tubes, Measuring cylinder, Test tube stand, Test tube holder, Delivery tube, Corks
Identification of Cations:
Identification test for Calcium Ion (Ca)
1. Flame Test:
Take a platinum wire and dip it in conc. HCl. Heat it strongly until the wire does not impart any colour to the non-luminous flame. Now dip the wire in solution of calcium salt solution in conc. HCl Heat it in the flame. Calcium imparts brick red colour t the flame which looks greenish-yellow through blue glass.
2. Solution of calcium salt in acetic acid gives a white precipitate with ammonium oxala solution
Identification test for Barium lon
1. Potassium chromate (K2CrO4) solution gives a yellow precipitate of barium chromate when the solution of Barium salt in acetic acid is treated with Potassium chromate.
2. Flame test: Take a platinum wire and dip it in conc. HCI. Heat it strongly until the win does not impart any colour to the non-luminous flame. Now dip the wire in the solution of Barium salt solution. Heat it in the flame. A grassy green colour of the flame confirms the presence of lead ions.
Identification test for Lead lon (Pb)
1. Lead sulphide dissolves in dilute HNO3. On adding dil. H2SO4 and a few drops of alcohol to this solution a white precipitate of lead sulphate appears.This indicates the presence of lead ions.
The white precipitate dissolves in ammonium acetate solution on boiling. When this solution is acidified with acetic acid and potassium chromate solution is added, a yellow precipitate of ICO, is formed. On adding potassium iodide solution, a yellow precipitate of lead iodide is formed.
Identification test for Zinc Ion
Identification of Anions
Aim: To perform the identification test of Anions as per IP
Identification of Sulphate lon:
Aqueous solution or sodium carbonate extract of the salt acidified with acetic acid on addition of barium chloride gives a white precipitate of barium sulphate ble in conc HC or conc. HNO3
Sulphate ions give white precipitate of lead sulphate when aqueous solution or sodium carbonate extract neutralised with acetic acid is treated with lead acetate solution.
Identification test for Carbonate ion
If there is effervescence with evolution of a colourless and odourless gas on adding dil H2SO4, to the solid salt, this indicates the presence of carbonate ion The gas turn lime water milky due to the formation of CaCO3
If Co, gas is passed in excess through lime water, the milkyness produced disappears due t the formation of calcium hydrogen carbonate which is soluble in water.
Identification test for Chloride ion
Salt solution containing chloride acidified with dilute HNO3 on addition of silver nitrate solution gives a curdy white precipitate soluble in ammonium hydroxide solution. The indicates the presence of Cl ions in the salt.
Identification Test for Phosphate ion
Add conc. HNO3 and ammonium molybdate solution to the test solution containing phosphate ions and boil. Yellow colouration in solution or a canary yellow precipitated ammonium-phosphomolybdate,
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