Which of the following does not give a white precipitate with ammoniacal $AgNO_3$?

$HC \equiv CH$ $\xrightarrow[{excess}]{{CH_3MgBr}} \mathop {(A)}\limits_{\text{salt}} + \mathop {(B)}\limits_{\text{hydrocarbon}}$
$(A)$ $\xrightarrow[{excess}]{{CH_3I}} (C)$ $\xrightarrow[{(ii) H^{+} }]{{(i) NaNH_2}} (D)$

$CH \equiv CH \mathop {\xrightarrow{Ni(CN)_2}}\limits_{Pressure} X$. Here,$X$ in the reaction is:

Complete the following reactions:
$(1)$ $CH \equiv CH + 2H_2 \xrightarrow[523-573 \ K]{Ni} ?$
$(2)$ $CH_3-C \equiv CH + 2H_2 \xrightarrow[or \ Ni, \Delta]{Pd \ or \ Pt} ?$

$But-2-yne$ 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:

Give a brief description of the structure of ethyne (acetylene).