ammoniumchloride

Ammonium chloride, with the formula NH4Cl, is a white, crystalline inorganic compound that readily forms colorless crystals and is highly soluble in water. It is hygroscopic and readily absorbs moisture from the air. In solid form it has a melting point of about 338 °C and, when heated further, thermally decomposes to give ammonia and hydrogen chloride gas.

Chemically, ammonium chloride consists of ammonium cations (NH4+) and chloride anions (Cl−). In aqueous solution it behaves as a mildly acidic salt, arising from the equilibrium that produces some free ammonia (NH3) and hydrogen ions.

Production and occurrence: Ammonium chloride is manufactured by reacting ammonia (NH3) gas with hydrogen chloride (HCl) gas to form NH4Cl. It can also be obtained as a byproduct in various industrial processes involving ammonia synthesis and gas scrubbing. It is not a naturally occurring mineral.

Uses: It is used as a flux in metallurgy to remove oxide films, particularly in soldering and brazing, and as a component in some metal-etching and galvanizing processes. Historically it has been used in medicine as an expectorant or cough suppressant and is employed as a food additive (E510) in some products as an acidity regulator and, in certain baked goods and candies, as a leavening aid.

Safety and handling: Ammonium chloride dust or solution can irritate the eyes, skin, and respiratory tract. It is corrosive in high concentrations and should be handled with appropriate protective equipment. It dissolves in water and, when released into the environment, contributes chloride ions; spills should be managed to prevent aquatic toxicity.