Question

Benzene react with chlorin in presence of sun light gives a compound (a). The compounds and its use are

Answer 1

Benzene reacts with chlorine or bromine in the presence of a catalyst, replacing one of the hydrogen atoms on the ring by a chlorine or bromine atom.

The reactions happen at room temperature. The catalyst is either aluminium chloride (or aluminium bromide if you are reacting benzene with bromine) or iron.