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

What is obtained when calcium carbide reacts with heavy water?

$0.40 \, g$ of an organic compound $(A)$ with molecular formula $C_5H_8O$ reacts with $x$ moles of $CH_3MgBr$ to liberate $224 \, mL$ of a gas at $STP$. Upon hydrogenation with excess $H_2$,$(A)$ yields pentan-$1$-ol. The correct structure of $(A)$ is:

Acetylenyl hydrocarbons are acidic because ..

Which of the following catalysts is used in the polymerization of $CH \equiv CH$ to $C_6H_6$?

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