I keep getting “Nucleophilic substitution” questions wrong in Haloalkanes & Haloarenes. What's the trap?
assuming every substrate reacts by the same mechanism.
The usual trap: assuming every substrate reacts by the same mechanism. How to avoid it: 3° favours SN1; 1° favours SN2; solvent and nucleophile decide too. Go back to the definition — a nucleophile replaces the halogen; it can go by SN1 (two steps, via a carbocation) or SN2 (one step, backside attack).
Key point
Nucleophilic substitution
Common mistake
assuming every substrate reacts by the same mechanism.
Memory tip
3° favours SN1; 1° favours SN2; solvent and nucleophile decide too.
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