The nitration of chlorobenzene gives major product as:

The correct answer is Option (3) → 1-Chloro-4-nitrobenzene

The chlorine atom of a haloarene acts on the ring in two opposite ways:

• By its −I effect it withdraws electrons and slightly deactivates the ring, so substitution is slower than in benzene.

• By resonance its lone pairs feed electron density into the ring, mainly at the ortho and para positions, so the incoming electrophile goes there.

In nitration the electrophile, the nitronium ion, is formed from the nitrating mixture:

    \( \displaystyle \ce{HNO3 + 2H2SO4 -> NO2+ + H3O+ + 2HSO4-} \)

It attacks the ortho and para positions of chlorobenzene:

    \( \displaystyle \ce{C6H5Cl + HNO3} \xrightarrow{\text{conc. }\ce{H2SO4}} \underset{\text{1-chloro-2-nitrobenzene (minor)}}{o\text{-}\ce{ClC6H4NO2}} + \underset{\text{1-chloro-4-nitrobenzene (major)}}{p\text{-}\ce{ClC6H4NO2}} + \ce{H2O} \)

The ortho positions lie next to the chlorine atom and are crowded, so the attack takes place mainly at the free para position. The major product is 1-chloro-4-nitrobenzene.

Why the other options are incorrect

• Option (1) 1-Chloro-2,4-dinitrobenzene — Incorrect. This is a dinitration product. A second nitro group goes in only under more drastic conditions, because the first –\( \ce{NO2} \) group strongly deactivates the ring.

• Option (2) 1-Chloro-2-nitrobenzene — Incorrect. It is formed, but as the minor product, because the ortho positions are hindered by the chlorine atom.

• Option (4) 1-Chloro-3-nitrobenzene — Incorrect. Resonance does not raise the electron density at the meta positions, so chlorine does not direct the electrophile there.

NCERT (2026-27 edition):
Electrophilic Substitution Reactions – “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.”