What is obtained by the reaction of calcium carbide with heavy water?

The reaction of $1,1,2,2$-tetrabromoethane with alcoholic zinc gives $..........$.

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

Which one is the correct order of acidity?

Acetylene is obtained by the electrolysis of

$0.40 \, g$ 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: