Chlorination of nitrobenzene gives only only one product

Question:
Why chlorination of nitrobenzene gives only m-chloro nitro benzene as major product?

Answer:

The reaction for chlorination of nitrobenzene is as follows

Ferric chloride is used as catalyst which is termed as halogen carrier

The catalyst reacts with chlorine to give chloronium ion which is the active reagent for chlorination reaction.

There are three positions on nitrobenzene where chloroniou ion can react and the resonating forms are as below:

In the resonating forms the structure marked as (I) and (II) are highly unstable structure because nitor group is electron withdrawing group and positive charge is present on the carbon atom which is directly attached to electron withdrawing group.

Thus the structure (I) and (II) are not the effective contributing structures in ortho and para substitution. But the resonating forms for meta substitution are relatively more stable that other two so chlorine gets substituted at  meta position forming  m-chloro nitrobenzene as the major porduct