WAEC - Chemistry (2011 - No. 43)

 To distinguish between ethene and ethyne: i Add a few drops of ammonical copper(I) chloride to each of ethylene (ethene) and acetylene (ethyne). No change will be observed in the case of ethylene (ethene) but in the case of acetylene (ethyne), a red precipitate of copper acetylide is formed. similar result

ii) When ammoniacal Silver Nitrate (AgNO3) is added to Ethyne then it gives white precipitates. But when Ammoniacal silver nitrate is added to Ethene then no reaction occurs and no precipitates obtain.