Propyne reacts with excess $HBr$ to form the compound $Z$. The structure of $Z$ is:

When treated with ammoniacal cuprous chloride,which one among the following forms a copper derivative?

Given below are two statements:
Statement $I$: One mole of propyne reacts with excess of sodium to liberate half a mole of $H_2$ gas.
Statement $II$: Four $g$ of propyne reacts with $NaNH_2$ to liberate $NH_3$ gas which occupies $224 \ mL$ at $STP$.
In the light of the above statements,choose the most appropriate answer from the options given below:

$But-2-yne$ and hydrogen (one mole each) are separately treated with $(i)$ $Pd / C$ and $(ii)$ $Na / \text{liq. } NH_3$ to give the products $X$ and $Y$ respectively. Identify the incorrect statements.
$A$. $X$ and $Y$ are stereoisomers.
$B$. Dipole moment of $X$ is zero.
$C$. Boiling point of $X$ is higher than $Y$.
$D$. $X$ and $Y$ react with $O_3 / Zn + H_2O$ to give different products.
Choose the correct answer from the options given below:

$1, 2$-Dibromopropane on treatment with $X$ moles of $NaNH_2$ followed by reaction with ethyl bromide gives $2$-pentyne. The value of $X$ is:

Two moles of $HBr$ are added to $CH_3-C \equiv CH$ in the presence of peroxide to give: