Calcium carbide on reacting with water gives

The general formula of an alkyne is:

The product$(s)$ obtained via oxymercuration $(HgSO_4 + H_2SO_4)$ of $1$-butyne would be:

The number of $\sigma$ and $\pi$ bonds between two carbon atoms in calcium carbide are

In the reaction
$HC \equiv CH \xrightarrow[(ii) CH_3CH_2Br]{(i) NaNH_2 / liq. NH_3} X$
$\xrightarrow[(ii) CH_3CH_2Br]{(i) NaNH_2 / liq. NH_3} Y$
$X$ and $Y$ are

What will be $Y$ in the following reaction?
$C_2H_2$ $\xrightarrow{O_3} X$ $\xrightarrow{Zn/CH_3COOH} Y$