Question

Identify correct reactivity order for $S_{N}2$ reaction.

• A. i > ii> iii
• B. ii > iii > i
• C. i > iii > ii
• D. None of these

Answer 1

The correct option is A i > ii> iii

$S_{N}2$ reactivity increases if the carbocation formed is least stable.

So, the cations formed are:

(II) is more stable due to inductive effect of 4-methyl groups at meta-position.

(III) is stable due inductive effect of 2-methyl group at meta

(i) is least stable.

So (i) has more reactivity towards $S_{N}2$

$\Rightarrow$ Ans :- i > iii > ii

$\Rightarrow$ Ans :- $C$