33.3.4—Hydrolysis reactivity: acyl vs alkyl chlorides

Acyl chlorides hydrolyse rapidly because the carbonyl carbon is strongly electrophilic and chloride is a good leaving group. Alkyl chlorides need suitable substitution conditions, while aryl chlorides resist because the C–Cl bond has partial double-bond character on an sp² carbon.

Compare the carbon attached to chlorine and the stabilisation of the possible intermediate before deciding reactivity.

Ethanoyl chloride reacts vigorously with water at room temperature; chloroethane reacts much more slowly under ordinary aqueous conditions; chlorobenzene is least susceptible.

All three contain chlorine, but hydrolysis rate is governed by the local structure, not the element alone.