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The presence of an electron-withdrawing group like -NO₂ at the **ortho** or **para** position of haloarene:
AIncreases the reactivity towards nucleophilic substitution by stabilising the carbanion intermediate via resonance; ortho/para — yes, meta — no effect
BHas no effect on reactivity
CDecreases the reactivity towards nucleophilic substitution
DCauses the C–X bond to break spontaneously
Answer & Solution
Correct answer: A. Increases the reactivity towards nucleophilic substitution by stabilising the carbanion intermediate via resonance; ortho/para — yes, meta — no effect
**EWG at o/p positions increases nucleophilic substitution reactivity** of haloarenes by stabilising the carbanion (Meisenheimer-type) intermediate via resonance — negative charge can rest on the C bearing -NO₂. **At meta position, no effect** because the resonance structures don't place negative charge near -NO₂.
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