Question

Consider the following reactions:
$\left(I\right){Me}_{3}C-Cl\underset{}{\overset{\stackrel{\ominus }{O}H}{\to }}{Me}_{3}C-OH$
$\left(II\right)F_{3}C-\underset{\underset{Me}{|}}{CH}-Cl\underset{}{\overset{\stackrel{\ominus }{O}H}{\to }}{F}_{3}C-\underset{\underset{Me}{|}}{CH}-OH$
$\left(III\right){Me}_{3}C-Cl\stackrel{90\%D_{2}O+10\%ether}{\to }{Me}_{3}C-OD$
$\left(IV\right){Me}_{3}C-Cl\underset{}{\overset{90\%D_{2}O+10\%ether}{\to }}{Me}_{3}C-OH$
Which of the following statements are correct?

• A. Reaction $\left(I\right)$ is faster than $\left(II\right)$
• B. Reaction $\left(II\right)$ is faster than $\left(I\right)$
• C. Reaction $\left(III\right)$ is faster than $\left(IV\right)$
• D. Reaction $\left(IV\right)$ is faster than $\left(III\right)$

Answer 1

Answer: (B), (D)

The correct options are
B Reaction $\left(II\right)$ is faster than $\left(I\right)$
D Reaction $\left(IV\right)$ is faster than $\left(III\right)$

i. In $\left(II\right)$, as shown in figure, carbocation is destabilised by stronger $-I$ effect of three F atoms, and thus solvolysis of $\left(II\right)$ is slower than that of $\left(I\right)$.
ii. D-bonds are not as stabilising as h-bonds. So reaction $\left(IV\right)$ is faster than $\left(III\right)$