Explanation

(d)
The given reaction can be represented as
$NaOH \rightarrow Na^{+} + OH^{-}$
[image:12_image323.emf]
Since in this reaction, a nucleophile replaces the other group, it is a example of nucleophilic substitution reaction.
The mechanism shows that the rate depends on the concentration of both alkyl halide and nucleophile. So, it is an example of $S_{N}2$(nucleophilic substitution of II order) reaction.