The copper cathode gains copper and becomes larger. The copper anode dissolves and becomes smaller.
For each copper (ll) ion discharged at the cathode, one copper anode the anode goes into the copper (ll) sulfate solution. Thus, the amount of copper (ll) sulfate in the solution and the colour of the solution change.
Producing Pure Copper
The electrolysis of copper (ll) sulfate solution, using copper electrodes, is used to refine (purify) copper.
The impure copper is made the anode. A piece of pure copper is used as the cathode. Pure copper from the anode goes into the electrolyte as copper (ll) ions. The copper (ll) ions get oxidized to copper, which is deposited on the cathode as pure copper. The impurities left on the anode fall off to collect below the anode. These impurities many contrain valuable silver and gold.
The copper produced in this process is 99.9 per cent pure. There are many uses of copper, including electrical wires and cables, and water pipes. Copper is also used in alloys such as brass and bronze.