Question

In the electrolytic refining of a metal “M”, what would you take as the anode, the cathode, and the electrolyte?

Answer 1

Electrolytic refining:

1. Electrolytic refining is a method of extracting and purifying metals obtained through refining processes.
2. The anode would be a rod of impure metal M, while the cathode would be a narrow strip of pure metal M. As an electrolyte, a water-soluble metal M salt would be utilized. When current is conducted through the electrolyte, the impure metal from the anode dissolves in the electrolyte and is replaced by an equal amount of pure metal from the electrolyte on the cathode.

Example of copper:

1. The electrolysis setup begins with an electrolytic tank containing an acidified copper sulfate solution as an electrolyte. After that, a thick block of impure copper metal is dipped to create an anode. A thin strip of pure copper metal is dipped to create a cathode.
2. Now that power has passed through the setup, impure copper from the anode dissolves and enters the ${\mathrm{CuSO}}_4$ solution, while pure copper from the copper sulfate solution deposits on the cathode. The cathode generates pure copper metal in this manner.
3. Insoluble pollutants settle down at the anode as anode mud, while soluble impurities go into the solution.
4. Reaction at the cathode: ${\mathrm{Cu}}^{+2}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Cu}\left(\mathrm{s}\right)$ and reaction at the anode: $\mathrm{Cu}\left(\mathrm{s}\right)\to {\mathrm{Cu}}^{+2}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}$

Therefore, on the cathode we take a pure metal, on the anode we take a rod of impure metal and the electrolyte would be of a metal that is water-soluble.