A

David

Darling

hydrogen chloride (HCl)

Hydrogen chloride (HCl) is a colorless acrid gas, fuming in air; a covalent hydride prepared by heating sodium chloride with concentrated sulfuric acid, or by direct combination of hydrogen and chlorine. It is unreactive when completely dry. In solution hydrogen chloride forms hydrochloric acid. Melting point -115°C; boiling point -85°C.