CBSE Class 12 · 2004 · All India Compartment · Alcohols Phenols and EthersVery Short Answer

How is phenol obtained from aniline?

Answer: Diazotise (NaNO₂/HCl, 273–278 K) then warm the diazonium salt with water: C₆H₅NH₂ → C₆H₅N₂⁺Cl⁻ → C₆H₅OH + N₂ + HCl.

Solution

Step 1 — diazotisation at 0–5 °C:

C_{6} H_{5} N H_{2} + NaN O_{2} + 2HCl \to C_{6} H_{5} N_{2}^{+} C l^{-} + NaCl + 2 H_{2} O

Step 2 — hydrolysis on warming:

C_{6} H_{5} N_{2}^{+} C l^{-} + H_{2} O Δ C_{6} H_{5} OH + N_{2} ↑ + HCl

CBSE Class 12 Board · 2004 · All India Compartment · Subjective