The reagent which is used to distinguish between propene and propyne is

$CH_3-C \equiv CH$ $\xrightarrow{Na} X$ $\xrightarrow{CH_3-Cl} Y$,$Y$ is

When acetylene is passed through a solution of dilute sulfuric acid containing mercuric sulfate,the number of $\pi$ bonds in the final product obtained is.........

The compound $X$ on reaction with $HgSO_4 + H_2SO_4$ gives $Y$ which on oxidation gives acetic acid. $X$ is

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

The synthesis of $3-$octyne is achieved by adding a bromoalkane into a mixture of sodium amide and an alkyne. The bromoalkane and alkyne respectively are