The general formula for an acyclic alkyne is.....

Ethyne on reaction with water in the presence of $HgSO_4$ and $H_2SO_4$ gives

What is the product formed when calcium carbide reacts with heavy water?

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:

Give a brief description of the structure of ethyne (acetylene).

$A$ hydrocarbon $X$ with molecular formula $C_4H_6$ decolourises bromine water and forms a white precipitate in ethanolic $AgNO_3$ solution. Treatment of $X$ with $HgCl_2$ in aqueous $H_2SO_4$ produces a compound,which gives a yellow precipitate when treated with $I_2$ and $NaOH$. The structure of $X$ is