Acetic acid when heated $\left(300°\mathrm{C}\right)$ with $\mathrm{MnO}$ gives:

If $\mathrm{X}$is $1,2-$addition product then identify $\mathrm{Y}$ in the following reaction sequence.

The end product in the above sequence of reactions is

${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{COCl}\underset{{\mathrm{H}}_2}{\overset{\mathrm{Pd}-{\mathrm{BaSO}}_4}{\to }} \mathrm{X}\stackrel{\mathrm{Oxidation}}{\to }\mathrm{Y}\underset{\mathrm{Dry} \mathrm{Distillation}}{\overset{\mathrm{Ca}-\mathrm{salt}}{\to }}\mathrm{A}$

$$Compound ($\mathrm{A}$) in above reaction sequence is

In the given reaction: