Haloalkanes and Haloarenes - Result Question 7
####7. Consider the reactions :
[2011 M]
$ \begin{align*} & (CH_3)_2 CH-CH_2 Br \xrightarrow{C_2 H_5 OH} \tag{i}\\ & \quad(CH_3)_2 CH-CH_2 OC_2 H_5+HBr \end{align*} $
(ii)
$ (CH_3)_2 CH-CH_2 OC_2 H_5+Br^{-} $
The mechanisms of reactions (i) and (ii) are respectively :
(a) $S_N 1$ and $S_N 2$
(b) $S_N 1$ and $S_N 1$
(c) $S_N 2$ and $S_N 2$
(d) $S_N 2$ and $S_N 1$
Show Answer
Solution:
- (a) First reaction is $S_N 1$ reaction because $C_2 H_5 OH$ is used as solvent which is a weak nucleophile.
Second reaction is $S_N 2$ reaction because $C_2 H_5 O^{-}$ is a strong nucleophile.
A strong nucleophile favours the $S_N 2$ reaction and a weak nucleophile favours the $S_N 1$ reaction.
