Question

A mixture of ${\mathrm{C}}_2{\mathrm{H}}_6$,${\mathrm{C}}_2{\mathrm{H}}_4$ and ${\mathrm{C}}_2{\mathrm{H}}_2$ is bubbled through an alkaline solution of Cuprous chloride. Which gas will come out?

Answer 1

Ethane ${\left({\mathrm{C}}_2{\mathrm{H}}_6\right)}_{}$:

• Ethane is a saturated hydrocarbon coming under the category of alkanes.
• It is found in the gaseous state.
• It contains two carbon atoms and six hydrogen atoms.
• Carbons have a single bond between them.
• Ethane is an important gaseous fuel.

Ethene $\left({\mathrm{C}}_2{\mathrm{H}}_4\right)$ :

• Ethene is an unsaturated hydrocarbon coming under the category of alkenes.
• It is found as a colorless gas with a faintly sweet odor.
• It contains two carbon atoms and four hydrogen atoms.
• Carbons have a double bond between them.
• It is highly soluble in organic solvents such as carbon tetrachloride and is sparingly soluble in water.

Ethyne $\left({\mathrm{C}}_2{\mathrm{H}}_2\right)$ :

• Ethyne is an unsaturated hydrocarbon coming under the category of alkynes.
• It is found as a colorless gas with a characteristic smell.
• It contains two carbon atoms and two hydrogen atoms.
• Carbons have a triple bond between them.
• It is significantly soluble in water but readily soluble in an organic solvent.

The reaction of Ethyne with alkaline Copper (I) chloride solution :

• When Ethyne is passed through ammoniacal Cuprous chloride solution, a red precipitate of Copper acetylide is formed.

$\mathrm{H}-\mathrm{C}\equiv \mathrm{C}-\mathrm{H}+{\mathrm{Cu}}_2{\mathrm{Cl}}_2+2{\mathrm{NH}}_4\mathrm{OH}\to \mathrm{Cu}-\mathrm{C}\equiv \mathrm{C}-\mathrm{Cu}+2{\mathrm{NH}}_4\mathrm{Cl}+2{\mathrm{H}}_2\mathrm{O}$

(Ethyne) (Cuprous chloride) (Ammonium hydroxide) (Copper acetylide) (Ammonium chloride) (Water)

• Alkaline solution of Copper (I) chloride does not react with Ethane (C₂H₆) and Ethene (C₂H₄), hence these will go out as gases.