Electrophilic addition reaction is easily given by

Options

A. Acetylene
B. Ethene
C. Ethane
D. Benzene

Answer

B

Explanation

Inspite of the fact that the two `pi`-bonds are present in alkynes, these are less reactive than alkenes towards addition reactions (due to symmetrical cylindrical nature of `pi` - electron cloud.) Further, alkynes do not show geometrical isomerism due to their linear structure.
The `pi` - electrons of alkynes are more tightly attached to the carbon atoms than `pi`-electrons in alkene and hence less easily available for addition reactions with electrophiles. As a result, alkynes are less reactive than alkenes towards electrophilic addition reaction. A majority of addition reactions of alkynes are catalysed by heavy metal ions such as `Hg^(2+)` and `Ba^(2+)` etc.while no such catalysts are needed in case of electrophilic addition reactions to alkenes.