Question

Which compound is formed as the final product $ B $?

• A. Phenol
• B. Benzene
• C. Aniline
• D. Benzenediazonium chloride

Hint:

Diazotization introduces the diazonium group ($ \text{N}_2^+ $) onto aromatic rings. Hydrolysis of diazonium salts typically replaces the diazonium group with a hydroxyl group ($ \text{OH} $).

Answer 1

The Correct Option is A

Step 1: Starting Material
The starting material is aniline, which has the structure: $$ \text{NH}_2 - \text{C}_6\text{H}_5 $$ Step 2: Diazotization Reaction
Aniline reacts with $\text{NaNO}_2 + \text{HCl}$ at low temperatures ($ 0^\circ \text{C} - 5^\circ \text{C} $) to form benzenediazonium chloride: $$ \text{C}_6\text{H}_5\text{N}_2^+ \text{Cl}^- $$ Step 3: Hydrolysis with Water
The diazonium salt is hydrolyzed with water at a warm temperature, resulting in the formation of phenol:
$$ \text{C}_6\text{H}_5\text{N}_2^+ \text{Cl}^- + \text{H}_2\text{O} \xrightarrow{\text{Warm}} \text{C}_6\text{H}_5\text{OH} + \text{HCl} $$ The final product is phenol: $$ \text{C}_6\text{H}_5\text{OH} $$