Question

Identify the reagent used in Etard reaction.

• A. \(\text{SnCl}_{2}\text{.HCl}\)
• B. \(\text{CrO}_{3}\)
• C. \(\text{Pd-BaSO}_{4}\)
• D. \(\text{CrO}_{2}\text{Cl}_{2}\)

Hint:

The Etard reaction converts toluene to benzaldehyde using a chromium reagent.

Answer 1

The Correct Option is D

Step 1: Compare Other Reagents
$\text{SnCl}_2/\text{HCl}$ is used in the Stephen reaction and $\text{Pd-BaSO}_4$ is used in the Rosenmund reduction.

Step 2: Chromium Reagents
$\text{CrO}_3$ is a general oxidising agent, not the Etard reagent.

Step 3: Conclusion
The Etard reagent is $\text{CrO}_2\text{Cl}_2$.

Final Answer:
The Etard reagent is chromyl chloride. \[ \boxed{\text{(D) }\text{CrO}_{2}\text{Cl}_{2}} \]