Hydrochloric Acid

Hydrochloric acid was discovered around A.D. 800 by Islamic alchemist Jabir Ibn Hayyam (Geber), by distilling common salt (NaCl) with sulphuric acid (H₂SO₄). It was known to European alchemists as spirit of salt or acidum salis. Gaseous HCl was called marine acid air. The old (pre-systematic) muriatic acid has the same origin (muriatic means "pertaining to brine or salt"). Hydrochloric acid is still sold under that name at industrial suppliers and hardware stores, for removing mortar stains and film from brickwork, masonry, and stonework.

Human digestive fluids consist of a mixture of hydrochloric acid and various enzymes which help break down proteins present in food.

Hydrochloric acid is now manufactured by combustion of chlorine gas in hydrogen to make hydrogen chloride gas followed by dissolution of the gas in water.

Hydrochloric acid is generally purchased in a concentrated form and is diluted in a fume cupboard, also kown as a fume hood (see making up solutions).

Unlike other strong acids, hydrochloric acid does not attack healthy skin.