Chrominfo: Identification test for zinc sulphate

Learn the identification test for zinc sulfate through a laboratory experiment or practical.

Aim:

To perform identification test for zinc sulphate.

Reference: Indian Pharmacopoeia (IP)

Requirements:

Glasswares and miscellaneous:

Test tube, measuring cylinder, pipette, glass rod, volumetric flask, beaker, funnel, dropper, rubber stopper, test tube stand, test tube holder, filter paper, balance, etc.

Chemicals:

Zinc sulphate (ZnSO4), sodium sulphide (Na2S), sodium hydroxide (NaOH), ammonium chloride (NH4Cl), ammonium mercuric thiocyanate (C4H8HgN6S4), cupric sulphate (CuSO4), barium chloride (BaCl2), potassium ferrocyanide (C6FeK4N6), lead acetate (Pb(C2H3O2)2), sulphuric acid (H2SO4), hydrochloric acid (HCl), etc.

Theory:

Identification tests are used to determine the drug's quality so that it can be used safely. This identification of ZnSO4 is usually based on the reactions of ions and cations present in the sample, by which we can determine the quality of the drug.

Zinc sulfate is an inorganic compound that comes as colorless, odorless, transparent crystals or white crystalline powder. Zinc sulphate is soluble in water and insoluble in ethanol. It is an efflorescent substance used as an astringent.

Procedure:

Identification tests for zinc ion:

Take 0.1 gm of sample and dissolved in 05.00 ml of distilled water, then add 0.2 ml of NaOH solution by which white precipitate is produced.
Take 0.1 gm of sample and dissolved in 05.00 ml of distilled water, acidify it with a dilute solution of sulphuric acid. Add a drop of cupric sulfate solution (0.1% w/v) and 02.00 ml of ammonium mercuric thiocyanate solution by which violet precipitate is formed.
Take 0.1 gm of sample and dissolved in 05.00 ml of distilled water, add 02.00 ml of potassium ferrocyanide solution forms a white precipitate that is insoluble in dilute hydrochloric acid.

Identification tests for sulphate ion:

Take 01.00 ml of barium chloride solution and add it to the sample solution. A white precipitate is formed due to the formation of ZnSO4.
Take 01.00 ml of lead acetate solution and add it to the sample solution. A white precipitate is formed due to the formation of lead sulphate.