6652. Nitrous Acid

Nomenclature

CAS number: 7782-77-6
HNO2; mol wt 47.01.
H 2.14%, N 29.80%, O 68.07%.

Description and references

Formed by the action of strong acids on inorganic nitrites. Review: Block, “Nitrous Acid, Hyponitrous Acid and their Salts” in Mellor's Vol. VIII, supplement II, Nitrogen (part 2) 353-408 (1967).

Properties

Known only in soln (pale blue in color). Weak acid. pK (25°) 3.35. In water it changes quickly into nitric oxide and nitric acid. Forms stable, water-sol nitrites with Li, Na, K, Ca, Sr, Ba, Ag. Does not form salts with weak polyvalent cations like Al or Be. Forms stable esters with alcohols.