Reaction of nitrous acid with Aromatic Primary amines
At 273 - 278 K, atomic primary amines react with sodium nitrite and dilute HCl, to give aromatic diazonium salts. For example, aniline forms benzene diazonium chloride.
Aromatic diazonium salts are stable only at low temperature. Hence at higher temperature, aromatic primary amine gives phenols.
Reaction of nitrous acid with Aromatic Primary amine
Aliphatic diazonium salts are highly unstable and hence alcohols are obtained when aliphatic primary amines are reacted with nitrous acid.