Question:
The reaction:
$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{I}+\mathrm{KOH}_{(a q)} \longrightarrow \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{KI}$
is classified as :
(a) electrophilic substitution
(b) nucleophilic substitution
(c) elimination
(d) addition
Solution:
$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{I}+\mathrm{KOH}_{(a q)} \longrightarrow \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{KI}$
It is an example of nucleophilic substitution reaction. The hydroxyl group of $\mathrm{KOH}\left(\mathrm{OH}^{-}\right)$with a lone pair of itself acts as a nucleophile and substitutes iodide ion in $\mathrm{CH}_{3} \mathrm{CH}_{2}$ t to form ethanol.