CBSE 2025 · Region 7 · Set 1 · Q20 · 2 marks
Why are haloarenes less reactive towards nucleophilic substitution reaction ? How does the presence of nitro $\displaystyle \left(-\mathrm{NO}_{2}\right)$ group at ortho- and para-positions in haloarenes increase the reactivity towards nucleophilic substitution reaction ?
Marking-scheme solution
-Because C—X bond acquires a partial double bond character due to resonance/ sp2
hybridized carbon of C-X bond leading to shorter bond length .
-Nitro group withdraws the electron density from the benzene ring and thus facilitates
the attack of the nucleophile on haloarene / -NO2 group being electron withdrawing
stabilises the intermediate carbanion.
Haloalkanes and HaloarenesChemical Reactions of Haloalkanes and HaloarenesUnderstandvery_short_answermedium
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CBSE Class 12 Chemistry past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.