In the given reactions identify the reagent A and reagent B

Toluene or substituted toluene is converted to benzylidene diacetate on treating with chromic oxide in acetic anhydride. The benzylidene diacetate can be hydrolysed to corresponding benzaldehyde with aqueous acid.

Chromyl chloride oxidises
methyl group to a chromium complex, which on hydrolysis
gives corresponding benzaldehyde. The reaction is known as Etard reaction.