Question

(i) Copy and complete the table.

	Anode	Electrolyte
Purification of Copper

Answer 1

Electrorefining

• An impure metal can be refined with the help of electrolysis and this process is known as electrorefining.
• Impure metal acts as anode while pure metal gets deposited at cathode.

Purification of copper via electrorefining:

• During the electrorefining of Copper, the electrolyte is aqueous copper sulfate $\left({\mathrm{CuSO}}_4\right)$ solution.
• Thick block of impure copper will act as anode while thin sheet of copper metal will act as cathode.

Reaction at the anode:

• Impure copper releases electrons from the anode and ${\mathrm{Cu}}^{2+}$ ions enter the electrolyte.

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

Reaction at the cathode:

• ${\mathrm{Cu}}^{2+}$ ions from electrolyte are reduced to copper metal atoms that get deposited at cathode.

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

The complete table is as follows:

	Anode	Electrolyte
Purification of Copper	Thick block of impure copper $\left(\mathrm{Cu}\right)$	Aqueous Copper sulfate solution $\left({\mathrm{CuSO}}_4\right)$