The hydrolsis of an ester gives a carboxylic acid, which on Kolbe's electrolysis yields ethane. The ester is

The end product $\mathrm{B}$ in the sequence of reactions,

$\mathrm{R}-\mathrm{X}\stackrel{{\mathrm{CN}}^{-}}{⟶}\mathrm{A}\stackrel{\mathrm{NaOH}}{⟶}$ is

In the reaction:

${\mathrm{CH}}_3\mathrm{CN}+2\mathrm{H}\underset{\mathrm{Ether}}{\overset{\mathrm{HCl}}{\to }}\mathrm{X}\underset{{\mathrm{H}}_2\mathrm{O}}{\overset{\mathrm{Boiling}}{\to }}\mathrm{Y};$ the term $\mathrm{Y}$ is: