Which of the following statements is correct?

Options

A. Alkynes are more reactive than alkenes in electrophilic addition reaction but less reactive in nucleophilic addition reactions.
B. Alkynes are more reactive than alkenes in nucleophilic addition reactions but less reactive in electrophilic addition reactions.
C. Alkynes are more reactive than alkenes in both electrophilic and nucleophilic addtion reactions.
D. Alkynes are less reactive than alkenes in both electrophilic and nucleophilic addition reactions.

Answer

B

Explanation

In the rate controlling step of electrophilic additions, alkynes form relatively less stable carbocation while in the rate controlling step of nucleophilic additions, alkynes form relatively more stable carbanions. For example, the three membered ring bromonium ion formed from the alkyne (I) has a full double bond causing it to be more strained and less stable than the one from the also, the C's of (I) that are part of the bromonium ion have more s character that those of (II), further making (I) less stable than (II).