What is the appropriate reagent for the following transformation?

   

Identify the product $\mathrm{X}$.

What is the product $\text{'}\mathrm{Z}\text{'}$ in the following reaction?

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}\underset{}{\overset{{\mathrm{PBr}}_3}{\to }}\mathrm{X}\stackrel{\mathrm{Alc}. \mathrm{KOH}}{\to }\mathrm{Y}\underset{\left(\mathrm{ii}\right) {\mathrm{H}}_2\mathrm{O}, \mathrm{heat}}{\overset{\left(\mathrm{i}\right) {\mathrm{H}}_2{\mathrm{SO}}_4, \mathrm{room} \mathrm{temperature}}{\to }}\mathrm{Z}$