Hydrocarbons

What is ' $ Y $ ' in the following set of reactions?

$$ \mathrm{C}_3 \mathrm{H}_4 \xrightarrow[\substack{\mathrm{Hg}^{2+} / \mathrm{H}^{+} \\ 333 \mathrm{~K}}]{\mathrm{H}_2 \mathrm{O}} X \xleftarrow[\substack{\text { (ii) } \mathrm{Zn}+\mathrm{H}_2 \mathrm{O}}]{\text { (i) } \mathrm{O}_3} Y $$