Aldehydes and ketones, having atleast one methyl group linked to the carbonyl carbon atom (methyl ketones), are oxidized by sodium hypohalite to sodium salts of corresponding carboxylic acids having one carbon atom less than that of carbonyl compound is converted to haloform. This oxidation does not affect a carbon-carbon double bond, if present in a molecule.

Which of the following aldehyde will give Aldol condensation?

(D)

The correct answer is (4) (D).

(A) The given molecule is benzaldehyde. Benzaldehyde does not undergo aldol condensation because benzaldehyde does not contain acidic \(α \) hydrogens in its structure.

(B) The compound (B) is 2,2-dimethylpropanol. The compound 2,2-dimethyl propanal has no \(α \)-hydrogen present in it and therefore, it cannot undergo aldol condensation.

(C) The compound is (E)-2-methyl-3-phenylacrylaldehyde. It does not undergo aldol condensation because (E)-2-methyl-3-phenylacrylaldehyd does not contain acidic \(α \) hydrogens in its structure.

(D) The compound is Cyclohexanone. When cyclohexanone undergoes aldol condensation in the presence of a base, it will produce a \(β−\) hydroxy ketone.