Consider the following reaction:

The product Z is:

Ethanol on heating with concentrated sulfuric acid at $170^{\circ }\text{C}$ ($443\text{K}$) undergoes dehydration to form ethene (${\text{CH}}_2={\text{CH}}_2$).Reaction: ${\text{C}}_2{\text{H}}_5\text{OH}\stackrel{{\text{conc. H}}_2{\text{SO}}_4/170^{\circ }\text{C}}{\to }{\text{CH}}_2={\text{CH}}_2+{\text{H}}_2\text{O}$.Wait, if the question asks for $Z$ in a multi-step sequence where $X$ is ethene, $Y$ is dibromoethane, $Z$ would be a dicyano compound. However, following the provided solution code (160 $\to$ 3), it results in ${\text{CH}}_3{\text{CH}}_2\text{OH}$.