Question

Identify the major products P and Q from the following set of reaction sequences:

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

Controlled oxidation of toluene gives benzaldehyde, while side-chain chlorination of toluene followed by hydrolysis can also give benzaldehyde.

Answer 1

The Correct Option is B

Step 1: Starting material.
The reactant is toluene, C₆H₅CH₃.

Step 2: Route to product P.
Controlled oxidation with CrO₃/(CH₃CO)₂O at 273 K followed by hydrolysis converts the side-chain –CH₃ into –CHO, giving benzaldehyde (P).

Step 3: Route to product Q.
Side-chain chlorination with Cl₂/hν followed by hydrolysis at 373 K also transforms the methyl group into an aldehyde, yielding benzaldehyde (Q).

Step 4: Final conclusion.
Both P and Q are benzaldehyde.