Nitrogen and Other P block Elements of Class 12
When primary aromatic amine is treated with nitrous acid in a cool solution, product is unstable compound, known as diazonium salt.
This reaction is known as diazotisation. Diazonium salts have the structure
Mechanism of diazotisation:
Illustration 28. Why ice cold condition have to be maintained in the diazotisation reaction of aniline?
Solution. Because benzene diazonium chloride is unstable and decomposed to give phenol above 278 K.
Reactions of diazonium salts:
These salts give substitution reactions and coupling reactions as follows: