Question

How copper is refined with an electrolytic method? Explain with necessary reactions.

Answer 1

Anode is the electrode where oxidation occurs and we can get metal from anode in ionic form after oxidation. At cathode, metal ions get reduced. Depending upon their reduction potential, we will get one metal deposited at cathode selectively.

Complete step by step solution:
We will see how copper is purified by electrolytic methods.
- We need an impure copper which is to be purified, a pure copper metal rod and a solution of copper in order to purify copper material by this method.
- We use impure copper metal as an anode in the electrochemical cell and the pure copper metal rod is used as a cathode. Both of the electrodes are dipped in a solution containing copper ions.
- Then the copper from the anode gets oxidized and forms copper ions. When copper ions reach the cathode, their reduction occurs and they get converted to pure copper metal and get collected at the cathode. The reaction at anode and cathode can be expressed as follows.

& \text{Anode: }C{{u}_{(s)}}\to C{{u}^{2+}}_{(aq)}+2{{e}^{-}}\text{ (Oxidation)} \\\ & \text{Cathode: }C{{u}^{2+}}_{(aq)}+2{{e}^{-}}\to C{{u}_{(s)}}\text{ (Reduction)} \\\ \end{aligned}$$ \- The impurity metals can dissolve or get collected at the bottom of the vessel depending upon their nature. \- The metals which are more basic than copper remain in the solution. The metals get collected at the bottom of the vessel in the form of anodic mud which are less basic than copper. **Thus, we can say that we can purify impure copper material by its electrolysis.** **Note:** Remember that we do not need to give any external electric energy to this cell. At anode, copper is oxidized to copper ions and at cathode, those ions get reduced to metallic copper. If we give external electric energy to this cell, it is possible that we may not get pure copper metal at cathode.