Alkenes undergo electrophilic addition reaction and benzene undergoes electrophilic substitution whereas both proceeds through carbocation intermediate. Explain.

Electrons are available in case of alkanes whereas they are delocalized in case 

of benzene. After attack of electrophile a stable delocalized carboncation is 

formed on benzene ring. Whereas a carbocation which can rearrange is formed 

by addition of electrophile on alkane.