Answer:
Diazonium salts are obtained when aniline is treated with nitrous (NaNO2 + HCl) acid at 273-278 K. In fact, these diazonium salts are extremely reactive. Such diazonium salts ultimately hydrolyze into phenols when heated with water. By treatment with dilute acids, phenols can be obtained from diazonium salts.
C6H5 – NH3 + (NaNO2 + HCl) →Diazonium salt →Phenol
