Question

aq KOH + Ketone

Answer 1

Aldol Condensation

Answer 2

Ketones possessing alpha-hydrogens undergo base-catalyzed aldol condensation in the presence of aqueous KOH. The base abstracts an alpha-hydrogen to form a resonance-stabilized enolate ion. This enolate then acts as a nucleophile, attacking the carbonyl carbon of another ketone molecule, leading to the formation of a beta-hydroxy ketone (ketol). Upon heating, the ketol can undergo dehydration to form an alpha,beta-unsaturated ketone.

For example, with acetone: $2 \text{CH}_3\text{COCH}_3 \xrightarrow{\text{aq KOH}} \text{CH}_3\text{COCH}_2\text{C(OH)(CH}_3)_2$ (Ketol: 4-hydroxy-4-methylpentan-2-one) $\text{CH}_3\text{COCH}_2\text{C(OH)(CH}_3)_2 \xrightarrow{\text{aq KOH, } \Delta} \text{CH}_3\text{COC(CH}_3)=\text{CHCH}_3 + \text{H}_2\text{O}$ (Unsaturated Ketone: 4-methylpent-3-en-2-one)