Question

(a) Give chemical tests to distinguish between
(i) Propanal and propanone,
(ii) Benzaldehyde and acetophenone.
(b) How would you obtain
( i) But-2-enal from ethanal
(ii) Butanoic acid from butanol,
(iii) Benzoic acid from ethylbenzene?

Answer 1

(i) Propanal and propanone
Tollen’s reagent test: Propanal being an aldehyde reduces Tollen’s reagent to silver mirror but propanone being a ketone does not.

(ii) Benzaldehyde and acetophenone
Iodoform test: Acetophenone being a methyl ketone on treatment with I₂/NaOH undergoes Iodoform reaction to give yellow ppt. of iodoform but benzaldehyde does not.