Question

Write chemical reactions for the following named organic reaction: 

Diazotisation reaction

Answer 1

In a Diazotisation reaction, a primary aromatic amine (like aniline) reacts with nitrous acid (HNO₂) at low temperature (0 - 5°C) to form a benzene diazonium salt.

Since nitrous acid is unstable, it is prepared in situ by reacting sodium nitrite (NaNO₂) with hydrochloric acid (HCl).

\[\ce{\underset{Aniline}{C6H5NH2} + NaNO2 + 2HCl ->[273 - 278 K] \underset{chloride}{\underset{Benzenediazonium}{C6H5\overset{+}{N2}\overset{-}{C}l}} + NaCl + 2H2O}\]