Question

$C\equiv C$ has two $\pi$ bond and it is _____ reactive than $-\underset{|}{C}=\underset{|}{C}-$ towards electrophilic addition reaction.

• A. less
• B. more
• C. equal
• D. none

Answer 1

The correct option is A less

The unsaturated C atom in alkene and alkyne is $s{p}^2$ and sp hybridized respectively. The percentage s character is 33.3 % and 50% respectively. Thus, alkyne C has more percentage s character which makes alkyne carbon more electronegative. Thus, in alkyne, the pi electrons are more strongly held by C atoms and hence, are less available for donation to electrophile.