Question

Identify the correct reagent for Etard reaction.

• A. \(CrO_2Cl_2,\ H_3O^+\)
• B. \(Pd-BaSO_4\)
• C. \(CrO_3,\ H_3O^+\)
• D. \(SnCl_2,\ HCl\)

Hint:

Etard reaction uses chromyl chloride \((CrO_2Cl_2)\) to convert the benzylic methyl group of an aromatic compound into an aldehyde without over-oxidation to the corresponding carboxylic acid.

Answer 1

The Correct Option is A

Step 1: Select the Etard oxidation reagent.
The Etard reaction oxidises toluene derivatives to benzaldehydes using chromyl chloride (CrO₂Cl₂) in CS₂/CCl₄, followed by aqueous acid hydrolysis. Pd-BaSO₄ is for Rosenmund reduction, CrO₃/H₃O⁺ is Jones oxidation, and SnCl₂/HCl reduces nitro groups.

Step 2: Final Answer:
CrO₂Cl₂, H₃O⁺ (option 1).