Which factor/s will increase the reactivity of group?
(i)Presence of group with positive inductive effect
(ii) Presenceof group with negative inductive effect
(iii) Presence of large alkyl group

Options

A. Only (i)
B. Only (ii)
C. (i) and (iii)
D. (ii) and (iii)

Answer

B

Explanation

The reactivity of the carbonyl group towards the addition reaction depends upon the magnitude of the positive charge on the carbonyl carbon atom. Hence, any substituent that increases the +ve charge on the carbonyl carbon must increase its reactivity towards addition reactions. The introduction of negative group (–I effect) increases the reactivity while introduction of alkyl group (+I effect) decreases the reactivity.
Large and bulky group creates hindrance in approach towards carbonyl carbon. So, large alkyl group decreases the reactivity of `gt C = O` group.