Question

The reagent used in the Etard reaction is:

• A. \( \text{Chromyl chloride (CrO}_2\text{Cl}_2) \)
• B. \( \text{Potassium dichromate (K}_2\text{Cr}_2\text{O}_7) \)
• C. \( \text{Chromic acid (H}_2\text{CrO}_4) \)
• D. \( \text{Sodium dichromate (Na}_2\text{Cr}_2\text{O}_7) \)

Hint:

The \textbf{Etard reaction} is a useful method for preparing \textbf{benzaldehyde} from \textbf{methyl-substituted aromatic compounds}. It utilizes \textbf{chromyl chloride} (\( \text{CrO}_2\text{Cl}_2 \)) as the key oxidizing agent, which is effective in oxidizing methyl groups to formyl groups.