Addition of $HCN$ to ethyne in the presence of $Ba(CN)_2$ as a catalyst gives:

An organic compound $X$ with molecular formula $C_6H_{10}$,when treated with $HBr$,forms a $gem$-dibromide. The compound $X$ upon warming with $HgSO_4$ and dil. $H_2SO_4$,produces a ketone,which gives a positive iodoform test. The compound $X$ is

Ethene can be separated from acetylene by passing the mixture through :

What is formed when acetylene reacts with alkaline $KMnO_4$?

$CH_3-CH_2-CH_2-C \equiv CH \xrightarrow[\text{Excess}]{HCl} ?$

Which of the following decolorizes $Br_2$ water solution?