$2-$butyne is reduced to $trans-but-2-ene$ using:

What are $X$ and $Y$ respectively in the following reaction?
$Z$-product $\stackrel{Y}{\longleftarrow} 2$-butyne $\stackrel{X}{\longrightarrow} E$-product

$A$ mixture of methane,ethylene,and acetylene gases is passed through a Wolf's bottle containing ammoniacal cuprous chloride. The gas coming out is

$A$ hydrocarbon with molecular formula $C_6H_6$ decolourises $Br_2$ water and gives a precipitate with ammoniacal $AgNO_3$. The hydrocarbon is:

$HC \equiv CNa + Cl - CH_2 - CH_2 - CH_2 - I \to (A)$; Major product $(A)$ is

$CH \equiv CH$ $\xrightarrow{O_3/NaOH} X$ $\xrightarrow{Zn/CH_3COOH} Y$. '$Y$' is: