Explain the regiochemical outcome for chlorination of bromobenzene.
Ortho attack and para attack are preferred because each of these pathways involves a sigma complex with____resonance structures. Attack at the meta position involves formation of a sigma complex with only_ resonance structures. The reaction will proceed more rapidly via the________ energy sigma complex, so attack takes place at the ortho and para positions in preference to the meta position.

In a chemical reaction, a particular reaction path may be favoured due to the fact that it is energetically more favourable(lower energy sigma complex is formed).

The more the resonance structures produced in a particular reaction pathway, the more energetically favourable it is.

In the chlorination of bromobenzene, ortho attack and para attack are preferred because each of these pathways involves a sigma complex with__4________resonance structures. Attack at the meta position involves formation of a sigma complex with only____3_______ resonance structures. The reaction will proceed more rapidly via the_____lower_______ energy sigma complex, so attack takes place at the ortho and para positions in preference to the meta position.