Give simple chemical tests to distinguish between the following pairs of compounds:
(i) Butanal and Butan−2−one
(ii) Benzoic acid and Phenol
(i) Tollen's reagent test: Add ammoniacal solution of silver nitrate (Tollen's Reagent) in both the solutions. Butanal gives silver mirror whereas Butan-2-one does not.(ii) Benzoic acid and phenol can be distinguished by ferric chloride test. Add neutral FeCl3 in both the solution, phenol forms violet colour but benzoic acid does not.