$1$-butyne can be distinguished from $2$-butyne by

$CH_{3}-C \equiv CH$ $\xrightarrow{2 HBr}$ $\xrightarrow{H_{2}O} \text{Product}$. The product is:

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

$A \xrightarrow{Ag_2O} \text{ppt}$
$A$ $\xrightarrow{Hg^{2+} / H^{+}} B$ $\xrightarrow{NaBH_4} C$ $\xrightarrow{conc. HCl / ZnCl_2} \text{Turbidity within 5 minutes}$.
Consider the following reactions,'$A$' is:

$CH_3-CH(CH_3)-C \equiv CH \xrightarrow{excess \ HBr}$
The product of the above reaction is

What is the product formed when $CH_3CH_2CHCl_2$ is treated with $NaNH_2$?