Laboratory preparation of ethyne

Ethyne is prepared by using water and calcium carbide in the laboratory.

Explanation:

Acetylene is conveniently prepared in the laboratory by the action of water (H₂O) on calcium carbide (CaC₂). Calcium carbide in turn is obtained by heating the mixture of coke and lime stone in an electric furnace.

CaC₂ + 2H₂O → Ca (OH) ₂ + C₂H₂

Ethyne gas prepared in the lab using the above method may contain impurities like H₂S, PH₃, AsH₃, NH₃etc. The gas is purified by bubbling it through acidified copper sulfate solution.