Which of the following reactions will yield $2,2$-dibromopropane as the product?

Which of the following compounds on hydration (addition of $H_2O$) with $H_2SO_4/HgSO_4/H_2O$ gives an aldehyde as the major product?

The following reaction is an example of a ....... reaction: $CH_2Br-CH_2Br + 2KOH (alc.) \xrightarrow{\Delta} CH \equiv CH + 2KBr + 2H_2O$

An unknown compound $X$ is an unsaturated hydrocarbon. It reacts with $HgSO_4$ and $H_2SO_4$ to give compound $(B)$. Compound $(B)$ on oxidation gives compound $(C)$. Compound $(C)$ on reaction with $NaOH$ and soda lime gives methane. Identify $A$ (which is $X$),$B$,and $C$ by providing the chemical reactions.

Identify the structures of $P$ and $Q$ in the following reaction sequence:

What is formed when calcium carbide reacts with heavy water?