In the reaction sequence, Ethene $\stackrel{\mathrm{HOCl}}{\to } \mathrm{A} \stackrel{\mathrm{X}}{\to }$ ethane$-1,2-$diol. $\mathrm{A}$ and $\mathrm{X}$ respectively are

  on treatment with conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$, predominately gives

The correct IUPAC name of the compound,

In the reaction, Ethanol$\stackrel{{\mathrm{PCl}}_5}{\to } \mathrm{X}\stackrel{\mathrm{alc}.\mathrm{KOH}}{\to } \mathrm{Y}\underset{298 \mathrm{K}}{\overset{{\mathrm{H}}_2{\mathrm{SO}}_4/{\mathrm{H}}_2\mathrm{O}}{\to }} \mathrm{Z}$. The $\text{'}\mathrm{Z}\text{'}$ is

The reaction above can be classified as: