Chrominfo: Identification test for magnesium sulphate

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

Aim:

To perform identification test for magnesium 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:

Magnesium sulphate (MgSO4), disodium hydrogen phosphate (Na2HPO4), sodium hydroxide (NaOH), ammonium chloride (NH4Cl), lead acetate (Pb(C2H3O2)2), barium chloride (BaCl2), ammonia solution, and titan yellow (C28H19N5Na2O6S4), etc.

Theory:

This identification of MgSO4 is usually based on the reactions of ions and cations present in the sample, by which we can determine the quality of the drug. Magnesium sulphate, also known as Epsom salt, is a salt with the formula MgSO4.7H2O that contains magnesium cations Mg2+ and sulphate anions SO2-4. It is a white crystalline solid, odorless, colorless crystal that is soluble in water and slightly soluble in ethanol in ethanol.

It works as an anticonvulsant, a calcium channel blocker, a cardiovascular drug, an anesthetic, a tocolytic agent, an anti-arrhythmia drug, an analgesic, and a fertilizer, among other things.

Procedure:

Prepare a sample solution by dissolving 01 g in 20 ml of distilled water and performing the tests listed below.

Identification tests for magnesium ion:

Take 02.00 ml of the prepared sample and add 01.00 ml of dilute ammonia solution. A white magnesium hydroxide precipitate is formed, which dissolves when 01.00 ml of 02 M ammonium chloride solution is added.
Add 01.00 ml of 0.25 M disodium hydrogen phosphate solution to 01.00 ml of the above solution. Magnesium ammonium phosphate appears as a white precipitate.
Add 0.2 ml of a 0.1 percent w/w titan yellow solution and 0.5 ml of 0.1 M NaOH to 0.5 ml of a neutral/slightly acidic solution of magnesium sulphate. A bright red turbidity forms, which settles into a bright red precipitate over time.

Identification tests for sulphate ion:

To the prepared sample solution, add 01.00 ml of barium chloride solution. Due to the formation of MgSO4, a white precipitate is formed.
To 01.00 ml of the above solution, add 01.00 ml of lead acetate solution. Because the formation of lead sulphate causes a white precipitate to be formed.