Question

Which of the following is a best example of $S_{N}2$ reaction?

• A. $C{H}_{3}Br+O{H}^{-}\to C{H}_{3}OH+B{r}^{-}$
• B.
• C. $C{H}_{3}C{H}_{2}OH\stackrel{-H_{2}O}{\to }C{H}_2=C{H}_2$
• D.

Answer 1

The correct option is A $C{H}_{3}Br+O{H}^{-}\to C{H}_{3}OH+B{r}^{-}$

$1^{\circ }$ alkyl halides, i.e., $C{H}_{3}Br$ generally undergoes $S_{N}2$ reaction.
Lesser the bulkier group attached to the attacking carbon, higher is its reactivity towards $S_{N}2$ reaction.
Hence, option A is correct.

Here, reaction (c) and (d) are not nucleophilic substitution reaction.