In the presence of sunlight, benzene reacts with Cl 2 to give product, X . The number of hydrogens in X is

In the presence of ultraviolet light (but without a catalyst present), hot benzene will also undergo an addition reaction with chlorine. The ring delocalisation is permanently broken, and a chlorine atom adds on to each carbon atom. 1,2,3,4,5,6-hexachlorocyclohexane or benzenehexachloride is formed as a product. It is an example of free radical addition reaction.