What is the type and number of bonds between carbon atoms in calcium carbide?

In the reaction $CH_3-C \equiv C-CH_3 \xrightarrow[(ii) H_2O/Zn]{(i) X} CH_3-CO-CO-CH_3$,what is $X$?

Write the following reaction:
$1$. Ozonolysis of ethyne.

The final product obtained by heating ethyne in the presence of $HgSO_4$ and dilute $H_2SO_4$ at $333 \ K$ is .........

An unknown compound $(A)$ has a molecular formula $C_4H_6$. When $(A)$ is treated with excess of $Br_2$, a new substance $(B)$ with formula $C_4H_6Br_4$ is formed. $(A)$ forms a white precipitate with ammoniacal silver nitrate solution. $(A)$ may be:

The major product in the following reaction is $H_3C-C\equiv CH + HBr$ (excess)