Question

How is phenol (carbolic acid) prepared from aniline (diazotization)?

Answer 1

Aniline is treated with nitrous acid [NaNO2 + HCl] at low temperature to obtain benzene diazonium chloride, which on hydrolysis gives phenol. This reaction is called diazotization. An aqueous solution of benzene diazonium chloride on warming with water or dil. H2SO₄ gives phenol.