During the electrolysis of copper chloride solution, describe what happens at each electrode, including the name of the product formed and the type of reaction occurring.

AQA GCSE Chemistry (8462) — 4.4.3 Electrolysis · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

At the cathode (negative electrode) Cu²⁺ ions are reduced to copper metal:

Cu²⁺ + 2e⁻ → Cu(s)

Copper metal is deposited on the electrode.

At the anode (positive electrode) Cl⁻ ions are oxidised to chlorine gas:

2Cl⁻ → Cl₂(g) + 2e⁻

Chlorine gas is released at the electrode.

Examiner tips

  • Use the word ‘reduction’ at the cathode and ‘oxidation’ at the anode; mention the products (Cu and Cl₂).
  • Show the half‑reactions to demonstrate electron transfer.
  • Keep the answer concise – one sentence per electrode is sufficient for full marks.

Common mistakes

  • Confusing the cathode with the anode or vice versa.
  • Writing the wrong product (e.g. CuCl instead of Cu).
  • Omitting the electron transfer (reduction/oxidation) in the description.

Mark scheme (4 marks)

  1. At the negative electrode (cathode), copper is produced
  2. At the negative electrode, positively charged copper ions gain electrons / reduction occurs
  3. At the positive electrode (anode), chlorine is produced
  4. At the positive electrode, negatively charged chloride ions lose electrons / oxidation occurs

Key terms in this question

electrolysis

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