In the reaction,$CH_3-C \equiv C-CH_3 \xrightarrow{(i) X, (ii) Zn/H_2O} CH_3-C(=O)-C(=O)-CH_3$,$X$ is:

In the reaction
$R - C \equiv C - R \xrightarrow{Pd + CaCO_3} B$
$R - C \equiv C - R \xrightarrow{Na + liq. NH_3} A$
$A$ and $B$ are geometrical isomers. Then:

The synthesis of $3$-octyne is achieved by adding a mixture of sodium amide and an alkyne to a bromoalkane. What are these bromoalkane and alkyne?

Acetylene can be obtained by the reaction:

Acetylene reacts with $HCN$ in the presence of $Ba(CN)_2$ to yield

The product $(B)$ of the reaction is:
$CH(CO_2H)=CH(CO_2H)$ $\xrightarrow[2 \ mole]{NaOH} (A)$ $\xrightarrow{\text{electrolysis}} (B)$