The homologue of ethyne is

In the following reaction,compound $A$ is formed,which reacts with $B$ to give product $C$. Identify $A$ and $B$.

Provide the primary information about alkynes.

The number of $\sigma$ and $\pi$ bonds between two carbon atoms in calcium carbide are

What is the product formed when two molecules of $HBr$ are added to $CH_3 - C \equiv CH$?

Which is the most suitable reagent among the following to distinguish compound $(3)$ from the others?
$(1) \ CH_3-C \equiv C-CH_3$
$(2) \ CH_3-CH_2-CH_2-CH_3$
$(3) \ CH_3-CH_2-C \equiv CH$
$(4) \ CH_3-CH=CH_2$