Nitrous acid

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Nitrous acid
Systematic name	Dioxonitric(III) acid
Molecular formula	HNO2
Molar mass	47.0134 g/mol
CAS number	10102-44-0
Density	? g/cm3
Solubility (water)
Melting point	? °C
Boiling point	? °C
Disclaimer and references

Nitrous acid (molecular formula HNO₂) is a weak (pKa~3.15) monobasic acid known only in solution and in the form of nitrite salts.

Nitrous acid is used to make diazides from amines; this occurs by nucleophilic attack of the amine onto the nitrite, reprotonation by the surrounding solvent, and double elimination of water. The diazide can then be liberated as a carbene.

Contents 1 Chemical structure 2 Preparation 3 Decomposition 4 Atmospheric relevence 5 See also

Chemical structure

Image:HNO2.gif

Preparation

It can be prepared by adding any mineral acid to sodium nitrite.

Decomposition

It rapidly decomposes into nitric acid, nitrogen monoxide and water when in solution.

Atmospheric relevence

Nitrous acid is an important atmospheric intermediate. It is produced by the heterogeneous reaction of NO₂ and water on various surfaces such as atmospheric aerosols. It is readily photolysed to produce hydroxyl radicals which are intricate in the ozone budget of the troposphere (lower atmosphere).

See also

• nitric acid (HNO₃)

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