Aldehyde And Ketone

What is ' $Z$ ' in the following reaction sequence?

$$ \mathrm{C}_3 \mathrm{H}_6 \xrightarrow[\mathrm{CCl}_4]{\mathrm{Br}_2} \underset{\text { (Colourless) }}{X} \xrightarrow[\text { (ii) } \mathrm{NaNH}_2, \Delta]{\text { (i) } \mathrm{KOH} / \text { Alcohol }} Y\xrightarrow[\substack{\mathrm{Hg}^{2+}, \mathrm{H}^{+} \\ 333 \mathrm{~K}}]{\mathrm{H}_2 \mathrm{O}} Z$$