Question

Account for the following :
(i) CH₃CHO is more reactive than CH₃COCH₃ towards reactionwith HCN.
(ii) Carboxylic acid is a stronger acid then phenol.

Answer 1

CH₃CHO is more reactive than CH₃COCH₃ towards reaction with HCNbecause the positive charge on carbonyl carbon of CH₃CHO decreases to a lesser extent due to one electron releasing ( +I effect ) CH₃ group as compared to CH₃COCH₃ ( two electrons releasing CH₃ group ) and hence more reactive
Acidity of carboxylic acid is higher thanalcohols and even phenols. Because , carboxylate ion, the conjugate base ofcarboxylic acid is stabilized by two equivalent resonance structures in which the negative charge is effectively delocalized between two more electronegative oxygen atoms.