Nitriittihapoilla

Nitriittihapoilla is the Finnish term for nitrous acid. Nitrous acid is a weak and unstable acid with the chemical formula HNO₂. It is typically encountered as an aqueous solution because it readily decomposes, especially when heated or in concentrated forms. In solution, nitrous acid exists in equilibrium with its conjugate base, the nitrite ion (NO₂⁻).

Nitrous acid is a significant reagent in organic and inorganic chemistry. In organic synthesis, it is famously used for the diazotization of primary aromatic amines, a reaction that forms diazonium salts. These diazonium salts are versatile intermediates for introducing various functional groups onto aromatic rings. In inorganic chemistry, nitrous acid is involved in redox reactions. It can act as both an oxidizing agent and a reducing agent, depending on the reaction conditions and the other species involved. For example, it can oxidize ammonia to nitrogen gas or be reduced by stronger oxidizing agents.

The production of nitrous acid is usually achieved by acidifying a solution of a nitrite salt, such as sodium nitrite (NaNO₂), with a strong acid like sulfuric acid (H₂SO₄) or hydrochloric acid (HCl). Due to its instability, it is generally prepared in situ for immediate use. The decomposition products of nitrous acid can include nitric oxide (NO), nitrogen dioxide (NO₂), and nitric acid (HNO₃).