There are various haloid derivatives of sulphurous acid.
It is decomposed by water into hydrofluoric and sulphurous acids.
Tin dissolves readily in strong hot hydrochloric acid as SnC12; aqueous sulphuric acid does not act on it appreciably in the cold; at 150° it attacks it more or less quickly, according to the strength of the acid, with evolution of sulphuretted hydrogen or, when the acid is stronger, of sulphurous acid gas and deposition of sulphur (Calvert and Johnson).
Other yeasts are stated to form sulphurous acid in must and wort.
Galvanized iron by its zinc surface is protected from corrosion by the weather, though the protection is not very efficient in the presence of acid or sulphurous fumes, and accordingly it is extensively employed for roofing, especially in the form of corrugated sheets.