Among the following cyclic ketones, which one exhibits the largest equilibrium constant for the addition of water (hydration)?

Step-by-step solution

The addition of water to a ketone (hydration) involves the nucleophilic attack of water on the carbonyl carbon, changing its hybridization from sp^2 to sp^3 . The ideal bond angle for an sp^2 hybridized carbon is 120^ , while for an sp^3 hybridized carbon it is 109.5^ . In cyclopropanone, the internal bond angle of the three-membered ring is constrained to 60^ . This results in severe angle strain for the sp^2 carbonyl carbon, as the deviation from the ideal angle is 120^ - 60^ = 60^ . Upon hydration, the carbonyl