The hydrocarbon which decolorizes alkaline `KMnO_4` solution but does not give any precipitate with ammoniacal silver nitrate solution is

The hydrocarbon which decolorizes alkaline KMnO_4 solution ,but does not give any precipitate with ammoniacal silver nitrate is :

The hydrocarbon which does not decolourise alkaline KMnO_4 solution and also does not give any precipitate with ammoniacal silver nitrate is

Which compound does not give precipitate with ammonical silver nitrate solution ?

A gas decolourises alkaline KMnO_(4) solution but does not give precipitate with silver nitrate. It is: