Which of the following will be the final product when $C_2H_2$ reacts with $HCl$?

Identify the compound $(Z)$ in the following reaction sequence: $CH_3-CH(Br)-CH_2Br$ $\xrightarrow{alc. KOH, \Delta}$ $\xrightarrow{NaNH_2}$ $\xrightarrow{H_2O, Hg^{2+}, H^+} (Z)$

The product $(B)$ is:

Write the following reactions:
$(1)$ Reaction of acetylene with $HCN$.
$(2)$ Hydrogenation of ethyne in the presence of Lindlar catalyst $(Pd, BaSO_4)$.

Which reagent is used to distinguish between propene and propyne?

Compound $(X)$ [styrene] is subjected to the following sequence of reactions: $(i)$ $Br_2/CHCl_3$, $(ii)$ $NaNH_2$ (excess), $(iii)$ $CH_3I$, $(iv)$ $H_2, Na/NH_3(l)$, giving Major Product $(Y)$. The molar mass of the major product $(Y)$ formed is . . . . . . $\text{g mol}^{-1}$. (Given molar mass in $\text{g mol}^{-1}$: $C:12, H:1$)