Question 51

Identify the conect statements:
The presence of - $$NO_{2}$$ group in benzene ring
A. activates the ring towards electrophilic substitutions.
B. deactivates the ring towards electrophilic substitutions.
C. activates the ring towards nucleophilic substitutions.
D. deactivates the ring towards nucleophilic substitutions.
choose the correct answer from the options given below :

The effect of the nitro group ($$-NO_2$$) on the benzene ring arises from its strong electron-withdrawing nature, which is due to both its $$-I$$ (inductive) and $$-M$$ (mesomeric/resonance) effects.

It pulls electron density away from the benzene ring.

Electrophilic aromatic substitution (EAS) requires electron density on the ring to attack the electrophile. Since $$-NO_2$$ withdraws electron density, it deactivates the ring towards electrophilic substitution. Statement B is correct.

Nucleophilic aromatic substitution (NAS) is favoured when the ring is electron-deficient, because the nucleophile attacks a carbon bearing a partial positive charge. Since $$-NO_2$$ makes the ring electron-poor, it activates the ring towards nucleophilic substitution. Statement C is correct.

Statement A (activates ring towards EAS) is incorrect because the nitro group instead deactivates the ring. Similarly, Statement D (deactivates ring towards NAS) is incorrect because it activates the ring towards nucleophilic substitution.

Therefore, the correct statements are B and C, which corresponds to Option 2.

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