JEE Main · 2022 · 26 Jul 2022 · Shift 2 · Alcohols Phenols and Ethers

Carbolic acid is another name for phenol ($\mathrm{C}{}_6\mathrm{H}{}_5\mathrm{OH}$). Benzenediazonium chloride ($\mathrm{C}{}_6\mathrm{H}{}_5\mathrm{N}{}_2{}^{+}\mathrm{Cl}{}^{-}$) undergoes hydrolysis in the presence of water and heat to give phenol. The reaction is: $\mathrm{C}{}_6\mathrm{H}{}_5\mathrm{N}{}_2{}^{+}\mathrm{Cl}{}^{-}+\mathrm{H}{}_2\mathrm{O}\stackrel{\mathrm{\Delta }}{\to }\mathrm{C}{}_6\mathrm{H}{}_5\mathrm{OH}+\mathrm{N}{}_2+\mathrm{HCl}$. This is a standard method for preparing phenol from aniline via diazotization followed by hydrolysis.