One mole of $1,2$-dibromopropane on treatment with $X$ moles of $NaNH_2$ followed by treatment with ethyl bromide gave a pentyne. The value of $X$ is

Give chemical reactions for the following conversions:
$1$. $2-$bromobutane from $2-$butyne
$2$. $2-$propanol and $1-$propanol from propyne

$CH_3-C \equiv C-CH_3 \xrightarrow{(i) X, (ii) H_2O/Zn} CH_3-CO-CO-CH_3$. $X$ in the above reaction is:

$But-2-yne$ 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:

The reagent used for converting acetylene to oxalic acid is

Heating a mixture of silver powder and $CHCl_3$ yields which compound?