Question

Which compound in each of the following pairs will react faster by  S_N1 reaction in aqueous KOH? Give reason :

(a) CH₃ – CH₂ – Br or CH₃ – CH₂ – Cl

(b) CH₃ – CH₂ – CH₂ – CH₂ – X or (CH₃)₃CX

Answer 1

(a) CH₃–CH₂–Br is more reactive towards S_N1 because it have good leaving group Rate of S_N1 ∝ Leaving tendency of leaving group

(b) (CH₃)₃C–X is more reactive towards S_N1,

due to formation of stable 3º carbocation. Rate of S_N1 ∝ Stability of carbocation