Question

Which of the following is used as reagent in Etard reaction?

• A. Chromium chloride
• B. Chromyl chloride
• C. Chromium oxide
• D. Chromic acid

Hint:

The formation of the brown chromium complex intermediate is what prevents the Etard reaction from continuing the oxidation process all the way to a carboxylic acid, making it highly valuable for synthesizing aldehydes.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The Etard reaction is a chemical reaction that involves the direct oxidation of an aromatic methyl group to an aldehyde group.

Step 2: Formula Application:
Reagent: $CrO_2Cl_2$ in $CS_2$.

Step 3: Explanation:
Toluene reacts with chromyl chloride ($CrO_2Cl_2$) to form a brown chromium complex, which on hydrolysis gives benzaldehyde. This specific oxidation of the methyl group to an aldehyde is the hallmark of the Etard reaction.

Step 4: Final Answer:
The reagent used is Chromyl chloride.