(i) Ethanal and Propanal: Ethanal and propanal can be distinguished by iodoform test. Warm each compound with iodine and sodium hydroxide solution in water. Ethanal gives yellow crystals of iodoform while propanal does not respond to iodoform test.
(ii) Phenol and Benzoic acid: On addition of NaHCO3 to both solutions, carbon dioxide gas is evolved with benzoic acid while phenol does not form CO2.
