Identify the reagent used in Etard reaction

Step-by-step solution

The Etard reaction involves the oxidation of a methyl group attached to an aromatic ring (such as toluene) to an aldehyde group (such as benzaldehyde). The reagent used for this specific transformation is chromyl chloride ( CrO₂Cl₂ ) in a non-polar solvent like CS₂ or CCl₄ , followed by hydrolysis. The reaction proceeds via the formation of a brown chromium complex, which upon decomposition with water yields the corresponding aldehyde. Answer: Chromyl chloride