Chrominfo: Identification test of ammonium chloride

Learn the identification tests for ammonium chloride through a laboratory experiment or practical.

Aim:

To perform an identification test for ammonium chloride.

Reference: Indian Pharmacopoeia (IP) 2010

Requirements:

Glasswares and miscellaneous:

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

Chemicals:

Ammonium chloride (NH4Cl), sodium hydroxide (NaOH), sodium cobalt nitrate (CoN6Na3O12), light magnesium oxide (MgO), silver nitrate (AgNO3), ammonia solution, potassium dichromate(K2Cr2O7), diphenylcarbazide (C13H14N4O), hydrochloric acid (HCl), nitric acid (HNO3), sulphuric acid (H2SO4), and methyl red solution, etc.

Theory of identification test for ammonium chloride:

The purpose of identification tests is to determine the quality of a drug so that it can be used safely. This identification of NH4Cl is usually based on the reactions of ions and cations present in the sample, by which we can determine the quality of the drug.

Ammonium chloride comes in the form of colorless, or white crystalline powder, odorless, with a saline flavor. It is used as a diuretic, expectorant, and systemic acidifier. It is slightly soluble in ethanol and easily soluble in water.

Procedure:

Identification tests for ammonium ion:

Heat a small amount of NH4Cl in a solution of sodium hydroxide.
Add 3-4 drops of sodium cobalt nitrate (10% w/v) to the ammonium chloride solution.
A yellow precipitate of ammonium cobalt nitrate is formed.
To the solution of ammonium chloride, add 0.2 gm of light magnesium oxide. Pass a flow of air through the mixture and direct the gas which is evolved just below the surface of the mixture of 01.00 ml of HCl (0.1 M) and 0.05 ml of methyl red solution. The solution color changes to yellow.

Identification tests for chloride ion:

Add 01.00 ml of dilute HNO3 solution to a 03.00 ml solution of ammonium chloride.
Then add a few drops of silver nitrate solution, resulting in a white silver nitrate precipitate.
When dilute ammonia is added, the precipitate dissolves due to the formation of a complex. (NH4CI + AgNO3 → AgCI+ NHNO3)
In a test tube, add 0.2 gm potassium dichromate and 01 ml sulphuric acid with a little amount of ammonium chloride. Cover the mouth of the test tube with a filter-paper strip soaked with 0.1 mL of diphenylcarbazide solution. The color of the paper changes to a violet-red color.