Strong oxidizing agents oxidize toluene and its derivatives to benzoic acids. However, it is possible to stop the oxidation at the aldehyde stage with suitable reagents that convert the methyl group to an intermediate that is difficult to oxidize further. The following methods are used for this purpose.

What will be the final product when toluene reacts with (i) CrO₃/ Ac₂O (ii) H₃O⁺?

Benzaldehyde + 2 CH₃COOH