Ammonium Chloride

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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NH₄Cl 53.49

Ammonium chloride.

Ammonium chloride CAS RN®: 12125-02-9; UNII: 01Q9PC255D.

Ammonium Chloride contains not less than 99.5 percent and not more than 100.5 percent of NH Cl, calculated on the dried basis.

1 Packaging and storage

Preserve in tight containers.

2 Identification

A solution (1 in 10) responds to the tests for Ammonium 〈191〉 and for Chloride 〈191〉.

pH 〈791〉: between 4.6 and 6.0, in a solution (1 in 20).

Loss on drying 〈731〉 - Dry it over silica gel for 4 hours: it loses not more than 0.5% of its weight.

Residue on ignition 〈281〉 - Add 1 mL of sulfuric acid to about 2 g, accurately weighed, and heat the mixture gently until volatilization is complete: the residue is white, and when ignited, not more than 0.1% of nonvolatile substance remains.

3 Limit of thiocyanate

Acidify 10 mL of a solution (1 in 10) with hydrochloric acid, and add a few drops of ferric chloride TS: no orange-red color is produced.

4 Assay

Transfer about 100 mg of Ammonium Chloride, accurately weighed, to a conical flask, add 10 mL of water, and swirl to dissolve. Add 10mL of glacial acetic acid, 75 mL of methanol, and 0.5 mL of eosin Y TS. Titrate, with shaking, with 0.1 N silver nitrate VS to a pink endpoint. Each mL of 0.1 N silver nitrate is equivalent to 5.349 mg of NH₄Cl.