Question

In the diazotization of arylamines with sodium nitrite and hydrochloric acid, an excess of hydrochloric acid is used primarily to 

(a) Supress the concentration of free aniline available for coupling 

(b) Supress hydrolysis of phenol 

(c) Ensure a stoichiometric amount of nitrous acid 

(d) Neutralise the base liberated

Answer 1

Correct option: (a) Supress the concentration of free aniline available for coupling

Explanation;

Excess of HCl is used to convert free aniline to aniline hydrochloride otherwise free aniline would undergo coupling reaction with benzenediazonium chloride.