[4K] Distinguish between Ethanal and Propanal | Why ethanal gives Iodoform test?Ethanal has a methyl ketone group which is the major cause of ethanal giving haloform test and iodoform formation. Also this property of ethanal enables us to use it to distinguish between all other aldehydes from ethanal. Aldehydes, Ketones and Carboxylic acids.