Question

Why ethylene is more reactive than acetylene towards electrophilic addition reaction?

Answer 1

Answer:

There are two reasons for less reactivity of Alkynes towards electrophillic addition reactions:-

Due to greater electronegativity of sp-hybridized carbon atoms of a triple bond than sp2 -hybridized carbon atoms of a double bond, pie-electrons of alkynes are more tightly held by the carbon atoms than pie electrons of alkenes and hence are less easily available for reaction with electrophiles. As a result the reactivity decrease.

The pie-electron cloud of alkyne makes a cylindrical electron cloud around the triple bond . Makes the electrons more delocalized and stable. And thr pie electrons are less available for an addition reaction.

Answer 2

Answer:

During addition reactions Both ethylene and acetylene forms carbonium ion intermediate. thus its the electronic factor which makes alkyne less reactive towards electrophillic attack.