(i) Distinction between acetaldehyde and benzaldehyde : - Acetaldehyde and benzaldehyde can be distinguish by Fehling solution.
Acetaldehyde gives red coloured precipitate with Fehling solution while benzaldehyde does not.
(ii) Propanone and propanal :- Propanal and propanone can be distinguished by their reactions with Tollens’ reagent.
Propanal will form the silver mirror, but propanone does not react.