question_answer

Chlorobenzene is ...... reactive than benzene towards electrophilic substitution and directs the incoming electrophile to the ...... position.

A)  more, ortho/para

B)  less, ortho/para

C)  more, meta      

D)  less, meta

Correct Answer: B

Solution :

-Cl group (-7) of chlorobenzene being deactivating, deactivates the benzene nucleus towards electrophilic substitution. Hence, chlorobenzene is less reactive as compared to benzene towards electrophilic substitution. Moreover chlorobenzene has the following canonical forms: From the above, it is clear that Cl-atom increases electron density at ortho and para-position. Thus, it directs the incoming electrophile to the ortho/para position.