In a set of reactions, ethyl benzene yielded a product $\mathrm{D}$ 

 

$\text{'}\mathrm{D}\text{'}$ Would be :-

 

This gives which isotopic product?

 $\mathrm{X} \& \mathrm{Y}$ respectively is -

Consider following reactions:

$\mathrm{Ph}-\mathrm{OH}\stackrel{\mathrm{Na}\text{ metal }}{\to }\text{ Gas }\mathrm{A}$

$\mathrm{Ph}-\stackrel{\mathrm{O}}{\stackrel{\left|\right|}{\mathrm{C}}}-\mathrm{OH}\stackrel{{\mathrm{NaHCO}}_{\mathrm{3}}}{\to }\text{Gas} \mathrm{B}$

The sum of molecular masses of gas $\mathrm{A}$ and $\mathrm{B}$ will be equal to:

The product is