Question

SN1 reaction underoges through a carbocation intermediate as follows : -

$\mathrm { R } - \mathrm { X }$ (aq.) $\stackrel { \mathrm { Slow } _ { \nu } } { \rightleftharpoons } \mathrm { R } ^ { + }$(aq.) $+ \mathrm { X } ^ { - }$(aq.) $\stackrel { \mathrm { H } _ { 2 } \mathrm { O } } { \text { fast } } \mathrm { ROH }$ (aq.) $+ \mathrm { H } ^ { + }$(aq.)

[R = t-Bu, iso-Pr, Et, Me] (X = Cl, Br, I)

The correct statements are

I. The decreasing order of rate of SN1 reaction is t-BuX > iso-PrX > EtX > MeX

II. The decreasing order of ionisation energy is MeX > EtX > iso-PrX > t-BuX

III. The decreasing order of energy of activation is t-BuX >

iso-PrX >EtX > MeX

• A. I & II are correct
• B. I & III are correct
• C. II and III are correct
• D. I, II & III are correct

Answer 1

Answer: (A)

I & II are correct

Answer 2

Rate of SN1 reaction is a

t Bu X > iso - PrX > EtX > MeX

So order of activation energy

t – BuX < iso PrX < EtX < MeX

order of ionisation energy

t BuX < iso PrX < EtX < MeX