Industrial Applications of Electrolysis - Purifying of Copper

  1. Copper is a good electrical conductor and is used extensively to make electrical wiring and components. However, the presence of impurity in copper can reduce its electrical conductivity.
  2. In industry, electrolysis processed is used to purify copper, and the process is called electrolytic refining.

Electrolytic Refining of Copper

  1. Figure above shows the illustration of the apparatus setup to investigate electrolytic refining of copper.
  2. When electricity flows, the copper in the impure anode dissolves in the solution to form copper ions.
  3. Copper ions are then deposit on the cathode which consist of a piece of pure copper.
  4. In SPM, you need to know
    1. the electrolyte used
    2. the electrode for the impure and pure copper
    3. the reaction at anode and cathode


Copper(II) sulphate

CuSO4 à Cu2+ + SO42-


Anode: Impure copper
Cathode: Pure copper

Chemical Reaction

Cu ---> Cu2+ + 2e

In anode, the copper atoms from the electrode are ionised to form copper(II) ions.

Cu2+ ---> Cu + 2e

In cathode, the copper ions are discharged to form copper atom and then deposit on the surface of the key

Note: Impurities in the copper do not dissolve, and instead fall off the anode as anode sludge. At the cathode, the copper ions are deposited as pure copper metal.

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