$1$-Alkyne and $2$-alkyne can be distinguished by

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

Which hydrocarbon can react with sodium in liquid ammonia?

$A$ hydrocarbon $X$ with molecular formula $C_4H_6$ decolourises bromine water and forms a white precipitate in ethanolic $AgNO_3$ solution. Treatment of $X$ with $HgCl_2$ in aqueous $H_2SO_4$ produces a compound,which gives a yellow precipitate when treated with $I_2$ and $NaOH$. The structure of $X$ is

The product$(s)$ obtained via oxymercuration $(HgSO_4 + H_2SO_4)$ of $1$-butyne would be:

To synthesize the unsymmetrical alkyne $CH_3-C\equiv C-CH_2-CH_3$,the reagents needed would be: