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Electrolysis is used to purify copper for applications in the electronics industry - Leaving Cert Chemistry - Question (b) - 2015
Question (b)
Electrolysis is used to purify copper for applications in the electronics industry. (i) Explain with the aid of a clearly-labelled diagram how impure copper is puri... show full transcript
Worked Solution & Example Answer:Electrolysis is used to purify copper for applications in the electronics industry - Leaving Cert Chemistry - Question (b) - 2015
Step 1
Explain with the aid of a clearly-labelled diagram how impure copper is purified by electrolysis.
Answer
Electrolysis involves using an electrolyte, typically a solution of copper(II) sulfate, and two electrodes: a cathode (negative) and an anode (positive). In the electrolysis setup:
- Setup: A power supply is connected to a solution containing copper(II) sulfate, where impure copper is used as the anode and pure copper is the cathode.
- Electrolytic Process: When current flows, copper ions () from the anode oxidize and migrate into the solution, while at the cathode, copper ions from the solution are reduced to pure copper, depositing onto the cathode surface.
- Diagram:
- Label the electrodes:
- 'Anode' (impure copper)
- 'Cathode' (pure copper)
- Label the electrolyte as 'Copper(II) sulfate solution'.
- Label the electrodes:
Thus, through this process, impure copper oxidizes, releasing copper ions into the solution, which then deposit as pure copper on the cathode.
Step 2
Step 3
What happens to impurities in the copper during this electrolysis?
Answer
During electrolysis, impurities that are not oxidized remain in the anode chamber. They tend to either fall to the bottom of the container or form a sludge called anode mud. This mud can contain valuable metals that can be recovered later. Therefore, while pure copper deposits on the cathode, the impurities are separated and do not transfer to the cathode.