Name the reaction to obtain benzaldehyde from:
i) toluene ii) benzene iii) benzoyl chloride. 

Explanation

i) Toluene : Toluene on oxisation with chromyl chloride `(CrO_(2)Cl_(2))` gives chromium complex, which on hydrolysis gives benzaldehyde. This reaction is called Etard.s reaction.

ii) Benzene : Benzene reacts with carbon monoxide and hydrogen chloride in the presence of anhydrous aluminium chloride and traces of cuprous chloride gives bnezaldehyde. This reaction is called Gatterman - Koch reaction.

iii) Benzoyl chloride : Benzoy: chloride on reduction with H, in presence of palladium catalyst supported by Barium sulphate gives benze aldehydes this reaction is called Rosenmund.s reduction.