Water is slowly dropped on small pieces of calcium carbide kept in a conical flask. The gas is collected by downward displacement of water as it is insoluble in water. Physical properties of ethyne The low molecular weighted alkynes such as ethyne, propyne and butyne are gases at room temperature. Alkynes with five to 13 carbon atoms are liquid at room temperature. Higher molecular weighted alkynes are solids at room temperature.
Alkynes are insoluble in water but are soluble in organic liquids.
Gaseous alkynes can produce a feeling of anesthesia when inhaled. Chemical properties of ethyne 1. Ethyne burns in air with a sooty flame. It forms carbon dioxide and water and gives out heat. The sooty flame is due to higher amount of carbon in ethyne than in methane.