Question

Give a simple chemical test to distinguish between benzaldehyde and ethanal.

Hint:

- The iodoform test distinguishes aldehydes with a methyl group next to the carbonyl group, like ethanal. - Benzaldehyde does not react with NaOH and I\(_2\), making it a useful distinguishing feature.

Answer 1

On heating with NaOH and I\(_2\), ethanal gives a yellow precipitate of iodoform (CHI\(_3\)), whereas benzaldehyde does not react. This reaction is known as the iodoform test, which is specific for aldehydes with a methyl group on the carbonyl carbon.