Question

Identify the product $B$ in the following reaction.
Toluene $\xrightarrow{\text{Chromyl chloride / CS}_2} A \xrightarrow{H_3O^+} B$

• A. Benzal chloride
• B. Benzaldehyde
• C. Benzyl alcohol
• D. Benzoic acid

Hint:

Chemistry Tip: This specific controlled oxidation of a methyl group on a benzene ring to an aldehyde using chromyl chloride is known as the Etard Reaction.

Answer 1

The Correct Option is B

Concept: Chemistry (Organic Chemistry) - Etard Reaction.

Step 1: Analyze the first step of the reaction. Toluene is treated with chromyl chloride ($CrO_2Cl_2$) in a solvent like carbon disulfide ($CS_2$).

Step 2: Identify intermediate A. The chromyl chloride oxidizes the methyl group of toluene to form a brown chromium complex as an intermediate (A).

Step 3: Analyze the second step (hydrolysis). The chromium complex (A) is then subjected to acid hydrolysis using $H_3O^+$.

Step 4: Identify the final product B. Hydrolysis of the complex yields benzaldehyde as the final product (B). $$ \therefore \text{The product B is Benzaldehyde.} $$