CH3CHO is more reactive than CH3COCH3 towards reaction with HCN.

Question

Account for the following :

CH₃CHO is more reactive than CH₃COCH₃ towards reaction with HCN.

Answer 1

Because 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 electron releasing CH₃ group) and hence more reactive.