Question

Consider the reactions
(i) $(C{H}_3{)}_{2}CH-C{H}_{2}Br\stackrel{C_2{H}_{5}OH}{\to }(C{H}_3{)}_{2}CH-C{H}_{2}O{C}_2{H}_5+HBr$
(ii) $(C{H}_3{)}_{2}CH-C{H}_{2}Br\stackrel{C_2{H}_5{O}^{-}}{\to }(C{H}_3{)}_{2}CH-C{H}_{2}O{C}_2{H}_5+B{r}^{-}$
The mechanisms of reactions (i) and (ii) are respectively.

• A. $S_{N}2$ and $S_{N}2$
• B. $S_{N}2$ and $S_{N}1$
• C. $S_{N}1$ and $S_{N}2$
• D. $S_{N}1$ and $S_{N}1$

Answer 1

The correct option is C $S_{N}1$ and $S_{N}2$

This reaction involve sN' mechanism.Stable carbocation form .As $C_2{H}_{5}OH$ is weak nucleophilic so $s_{N}1$ mechanism followed

2)$(C{H}_3{)}_{2}CHC{H}_{2}Br⟶(C{H}_3{)}_{2}CHC{H}_{2}O{C}_2{H}_5+B{r}^{-}$

as strongnucleophilic is involved so give reaction go by $s{N}^2$ mechanism.