Question

Describe what would you observe at the anode and the cathode during electrolysis of Copper chloride (II) using platinum cathode and carbon anode. Write ionic equations for the reactions at the anode and the cathode.

Answer 1

Electrolysis

The process of decomposing ionic compounds into their constituent components by passing an electric current through them in an aqueous or molten form is known as electrolysis.

Ionic equation for the electrolysis of Copper(II) chloride

${\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)\to \mathrm{Cu}\left(\mathrm{s}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)$

The reaction at the cathode:

• The Copper ions $\left({\mathrm{Cu}}^{2+}\right)$ have the lowest reduction potential. Thus, they are discharged in preference to ${\mathrm{H}}^{+}$ ions to form neutral Copper atoms. The Copper atoms get deposited at the cathode.

${\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Cu}\left(\mathrm{s}\right)$

• Reduction takes place at the cathode.

The reaction at the anode:

• The Hydroxyl and Chloride ions are migrated towards the anode. Only Chloride ions are discharged in small quantities. The Chloride ions are oxidized by the electron loss, leading to the formation of Chlorine gas at the anode.

$2{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)-2{\mathrm{e}}^{-}\to {\mathrm{Cl}}_2\left(\mathrm{g}\right)$

• The oxidation takes place at the anode.

Hence, the reactions at the anode and the cathode are discussed above.