$2-$Butyne reacts with $Na$ in liquid $NH_3$ to form:

The major product $(A)$ is:

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

Consider the following reaction sequence:
$CH_3CH_2CH_2CH(Br)CH_2Br + 2NaNH_2 \rightarrow X$
$X \xrightarrow[(ii) (CH_3)_2CHBr]{(i) NaNH_2} Y$
The product $Y$ formed is:

An unknown compound $X$ is an unsaturated hydrocarbon. It reacts with $HgSO_4$ and $H_2SO_4$ to give compound $(B)$. Compound $(B)$ on oxidation gives compound $(C)$. Compound $(C)$ on reaction with $NaOH$ and soda lime gives methane. Identify $A$ (which is $X$),$B$,and $C$ by providing the chemical reactions.

Benzene is the polymer of