When ${\mathrm{CH}}_3{\mathrm{CHOHCH}}_3$ is reacted with ${\mathrm{PCl}}_5$, 2-Chloropropane is formed. Thus, X is 2-Chloropropane ${\mathrm{CH}}_3{\mathrm{CHClCH}}_3$.

When ${\mathrm{CH}}_3{\mathrm{CHOHCH}}_3$ is reacted with alc. KOH , Propene is formed. Thus, Y is ${\mathrm{CH}}_3-\mathrm{CH}={\mathrm{CH}}_2$.

When ${\mathrm{CH}}_3-\mathrm{CH}={\mathrm{CH}}_2$ is treated with conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$ and ${\mathrm{H}}_2\mathrm{O}$, 2-Propanol ${\mathrm{CH}}_3{\mathrm{CHOHCH}}_3$ is formed. Thus Z is ${\mathrm{CH}}_3{\mathrm{CHOHCH}}_3$.