Question

Draw a neat and well-labelled diagram for electrolytic refining of copper.

Answer 1

Electrolytic refining of copper:

• In the electrolytic purification of copper, impure copper is made into an anode and a thin line of pure copper is made into a cathode, a copper salt solution is used as an electrolyte.
• When the current passes through the electrolyte, the pure metal from the anode melts into an electrolyte.
• An equal amount of pure metal from the electrolyte is inserted into the cathode.
• Soluble impurities enter the solution, whereas, soluble impurities settle to the bottom of the anode and are known as anode mud.
• The following reactions occur at anode and cathode:

$$\begin{gathered} \mathrm{At}\mathrm{anode}:\mathrm{Cu}\left(\mathrm{s}\right)\to {\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-} \\ \mathrm{At}\mathrm{cathode}:{\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Cu}\left(\mathrm{s}\right) \end{gathered}$$

Electrolytic refining of copper takes place using apparatus shown below: