Question

Aldol condensation does not occur between

• A. two different aldehydes
• B. two different ketones
• C. an aldehyde and a ketone
• D. an aldehyde and an ester

Answer 1

Answer: (D)

an aldehyde and an ester

Answer 2

Aldol condensation occurs in between two moles of carbonyl compounds among which at least one must have a-hydrogen atom, in dilute basic media. This results in the formation of $\beta$ -hydroxyaldehyde or ketones and finally a, $p$-unsaturated aldehydes or ketones. As ester $(R - \overset{\underset{||}{O}}{C} - O - R$ does not contain a reactive carbonyl group,
so it does not perform aldol condensation.