Iso-butylene when subjected to hydroboration oxidation reaction yields

Identify the final product, ${\mathrm{CH}}_2={\mathrm{CH}}_2\stackrel{{\mathrm{Cl}}_2/{\mathrm{H}}_2\mathrm{O}}{⟶}\mathrm{X}\stackrel{\mathrm{aq}.\mathrm{KOH}}{⟶}\mathrm{Y}$

What is $\mathrm{Z}$ in the following sequence of reactions?

$\mathrm{Z}\stackrel{{\mathrm{PCl}}_5}{\to }\mathrm{X}\stackrel{\mathrm{AlC}.\mathrm{KOH}}{\to }\mathrm{Y}\underset{\left(\mathrm{ii}\right){\mathrm{H}}_2\mathrm{O}; \mathrm{boil}}{\overset{\left(\mathrm{i}\right)\mathrm{Conc}.{\mathrm{H}}_2{\mathrm{SO}}_4}{\to }}\mathrm{Z}$