Formation of ethylene from acetylene is an example of

Identify the major product of the following reaction:

Identify $X$ in the following sequence of reactions.
$CH_3-CH(Br)-CH(Br)-CH_2-CH_2-CH_3 \xrightarrow[(ii) Na \text{ in liquid } NH_3]{(i) NaNH_2} X$

What is the type and number of bonds between carbon atoms in calcium carbide?

When acetylene is passed through a solution of dilute sulfuric acid containing mercuric sulfate,the number of $\pi$ bonds in the final product obtained 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: