Benzoic acid on nitration with a mixture of concentrated nitric acid and concentrated sulphuric acid gives m-nitrobenzoic acid as the main product. In this reaction, the carboxyl group acts as:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A deactivating and meta-directing group
The carboxyl group withdraws electrons from the benzene ring. The ring becomes poorer in electrons, so it reacts with electrophiles more slowly than benzene does: the group is deactivating. The ortho and para positions lose more electron density than the meta position, so the nitro group enters the meta position:
\( \displaystyle \ce{C6H5COOH + HNO3} \xrightarrow{\text{conc. }\ce{H2SO4}} \ce{O2N-C6H4-COOH + H2O} \quad \text{(m-nitrobenzoic acid)} \)
Why the other options are incorrect
Option (1) An activating and ortho/para-directing group — Incorrect. This describes groups that release electrons to the ring, such as –OH in phenol or –CH3 in toluene; they give ortho and para products.
Option (3) An activating and meta-directing group — Incorrect. A group that sends the electrophile to the meta position does so because it pulls electrons out of the ring, so it cannot also activate the ring.
Option (4) A deactivating and ortho/para-directing group — Incorrect. This describes the halogens, as in chlorobenzene. The carboxyl group gives the meta product, not ortho and para products.
NCERT (2026-27 edition):
8.9.4 Substitution Reactions in the Hydrocarbon Part – “2. Ring substitution
Aromatic carboxylic acids undergo electrophilic substitution reactions in which the carboxyl group acts as a deactivating and meta-directing group.”