Which of the following gives propyne on hydrolysis?

$CH \equiv CH + HBr \to X$,the product $X$ is:

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:

How many structures are possible for $C_5H_8$ with one triple bond?

The reagents to carry out the following conversion are:

$CH_3-C \equiv C-CH_3$ $\xrightarrow{NaNH_2}$ $X$. What is $X$?