JEE Main 2017 · 2 Apr · Shift 1 · Chemistry Q55

ChemistrySingle correct+4 / -1Question 55 of 90

The increasing order of the reactivity of the following halides for the $S_N1$ reaction is :

(I) $\ce{CH3CH(Cl)CH2CH3}$ ; (II) $\ce{CH3CH2CH2Cl}$ ; (III) $p\text{-}\ce{H3CO-C6H4-CH2Cl}$

(I) < (III) < (II)

(II) < (III) < (I)

(III) < (II) < (I)

(II) < (I) < (III)

Answer and worked solution

Official answer: D

$S_N1$ rate follows carbocation stability: primary (II) < secondary (I) < p-methoxybenzyl (III), which is resonance-stabilised.

JEE Main 2017 · 2 Apr · Shift 1, Chemistry question 55