chemistry·NCERT Class 12·Haloalkanes & Haloarenes

SN1 vs SN2 Mechanism

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CH₃Br reacts with OH⁻ in one direct backside attack. But (CH₃)₃CBr can't — the three methyls block the path. Watch the mechanisms step by step.

SN2: one step, backside attack, Walden inversion, rate = k[RX][Nu⁻].
SN1: two steps — ionisation (slow, RDS) → carbocation + nucleophile attack.