True. When benzene reacts with chlorine (Cl2) in the presence of a catalyst like iron(III) chloride (FeCl3), the primary product of the reaction is chlorobenzene.
This reaction is an example of electrophilic aromatic substitution, where the hydrogen atom on the benzene ring is replaced by a chlorine atom. The role of FeCl3 is to generate a more reactive chlorine species that facilitates this substitution. As a result, chlorobenzene is formed as the main product, although there can be trace amounts of other chlorinated compounds. In most cases, however, the predominant product is indeed chlorobenzene.