💯 Nucleophilic Substitution Revision Q&A – Haloalkanes & Haloarenes (Class 12 Chemistry) Q: What is a nucleophilic substitution reaction ? A: A reaction in which a nucleophile replaces a leaving group , typically a halide, from an organic substrate. Q: Name two main mechanisms of nucleophilic substitution in haloalkanes . A: SN1 (unimolecular) and SN2 (bimolecular) mechanisms. Q: Which carbon hybridization is most favorable for nucleophilic substitution? A: sp 3 -hybridized carbon. Q: Why do haloarenes undergo nucleophilic substitution with difficulty? A: Due to resonance stabilization and partial double bond character in C–X bond. Q: What is the order of reactivity for SN2 mechanism: methyl, 1°, 2°, or 3° alkyl halides? A: Methyl > 1° > 2° > 3°. Q: What is the order of reactivity for SN1 mechanism: methyl, 1°, 2°, or 3° alkyl halides? A: 3° > 2° > 1° > methyl. Q: What determines the rate of SN1 reaction? A: Conc...