Why haloarenes (chlorobenzene) undergoes electrophilic substitution reactions slowly than benzene?

Dear Student,

Please find below the link of a similar query as asked by you: 

https://www.meritnation.com/ask-answer/question/why-does-benzene-undergo-electrophilic-substitution-reaction/hydrocarbons/6326464

https://www.meritnation.com/ask-answer/question/why-chlorobenzene-is-less-reactive-towards-nucleophilic-sub/haloalkanes-and-haloarenes/5397878

We hope the above link will help you in clearing the doubt.

Regards