Distinction between $pent-1-ene$ and $pent-1-yne$ is done by:

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

The treatment of $CH_3MgX$ with $CH_3-C \equiv CH$ produces

Identify $A$ in the following reaction.
$A$ $\xrightarrow{\text{Lithium amide}} \text{Ethynyl lithium}$ $\xrightarrow{\text{Bromoethane}} \text{but-}1\text{-yne}$

$CaC_2 + H_2O \to A \xrightarrow{H_2SO_4/HgSO_4} B$. Identify $A$ and $B$ in the given reaction.

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