Oxidation of toluene to Benzaldehyde can be easily carried out with which of the following reagents?

Step 1: Understand the reaction

Toluene is C₆H₅–CH₃

We want to oxidize the –CH₃ group only up to –CHO (aldehyde) to get benzaldehyde.

Step 2: Check the reagents

CO / HCl, AlCl₃ → This is Friedel–Crafts formylation. It works but requires special conditions.

CrO₃ / acetic acid, H₃O⁺ → Mild oxidizing conditions. Stops at aldehyde, does not go further to carboxylic acid. 

KMnO₄ / HCl, H₃O⁺ → Strong oxidizer. Oxidizes toluene all the way to benzoic acid, not benzaldehyde. 

CrO₃ / acetic anhydride, H₃O⁺ → Stronger, usually used in Jones or similar oxidations.

To get benzaldehyde, we need a mild oxidizing agent that stops at –CHO.

CrO₃ in acetic acid, followed by H₃O⁺ does exactly that.

Answer: Option B