Question

An organic compound \(A\) with molecular formula \(C_7H_6O\) forms 2,4-DNP derivative and reduces Tollens' reagent. When \(A\) is heated with conc. KOH, it gives sodium benzoate and compound \(B\). The compound \(B\) is

• A. Benzene
• B. Toluene
• C. Acetophenone
• D. Benzaldehyde
• E. Benzyl alcohol

Hint:

Aldehyde without alpha hydrogen undergoes Cannizzaro reaction to give alcohol and carboxylate salt.

Answer 1

Answer: (E)

Concept: Benzaldehyde gives 2,4-DNP test and Tollens' test. It undergoes Cannizzaro reaction with concentrated KOH because it has no alpha hydrogen.

Step 1: Identify compound \(A\).
Molecular formula \(C_7H_6O\), positive 2,4-DNP and Tollens' test indicate: \[ A = \text{Benzaldehyde} \]

Step 2: Cannizzaro reaction.
Benzaldehyde with concentrated KOH gives: \[ \text{Sodium benzoate} + \text{Benzyl alcohol} \]

Step 3: Identify \(B\).
Hence: \[ B = \text{Benzyl alcohol} \]