Haloarenes undergo the usual electrophilic reactions of the benzene ring such as halogenation, nitration, sulphonation and Friedel-Crafts reactions. Halogen atom besides being slightly deactivating is o, p-directing; therefore, further substitution occurs at ortho- and para-positions with respect to the halogen atom. Due to resonance, the electron density increases more at ortho- and para-positions than at meta-positions. Further, the halogen atom because of its –I effect has some tendency to withdraw electrons from the benzene ring. As a result, the ring gets somewhat deactivated as compared to benzene and hence the electrophilic substitution reactions in haloarenes occur slowly and require more drastic conditions as compared to those in benzene.

What is the major product formed when chlorobenzene reacts with Sulphuric acid?

4-Chlorobenzenesulphonic acid

The correct answer is option 3. 4-Chlorobenzenesulphonic acid.

When chlorobenzene reacts with sulphuric acid, the major product is 4-Chlorobenzenesulphonic acid. The sulphonation of chlorobenzene, which is an electrophilic aromatic substitution reaction, leads to the formation of the sulphonic acid group primarily at the para position relative to the chlorine atom. This is because the chlorine atom is an ortho/para-directing group due to its electron-donating resonance effect, despite being deactivating overall due to its inductive effect. The para position is favored due to reduced steric hindrance compared to the ortho position.

So, the correct answer is 4-Chlorobenzenesulphonic acid.