Question

In laboratory, ethylene and acetylene can be distinguished by

Answer 1

1.When acetylene is bubbled through ammoniacal silver nitrate solution , a yellow-white precipitate of silver acetylide would be formed.

     C2H2 + 2AgNO3 = Ag2C2 + 2HNO3

2. Similarly, acetylene forms a red precipitate of copper acetylide (Cu2C2) when it is passed through ammoniacal cuprous chloride solution.

Ethylene does not react with AgNO3 or Cu2Cl2 solution.

Answer 2

Hey dear,
Just to clear, ethylene = ethene & acetylene = ethyne.

● Chemical test to distinguish ethylene and acetylene -
Acetylene molecule have acidic hydrogen and thus reacts with basic cuprous chloride soln to give red ppt of copper acetylide.
CH≡CH + Cu2Cl2 + NH4OH --> Cu-C≡C-Cu + NH4Cl + 2H2O

Ethylene doesn't have acidic hydrogen and thus don't react with ammoniacal cuprous chloride.
CH2=CH2 + Cu2Cl2 + NH4OH --> NO REACTION

Hope this helps you...