ElectrolysisComparison

Half Equations — Must Know!

Part of Electrolysis of Aluminium · GCSE GCSE Chemistry revision

This comparison covers Half Equations — Must Know! within Electrolysis of Aluminium for GCSE Chemistry. Revise Electrolysis of Aluminium in Electrolysis for GCSE Chemistry with 21 exam-style questions and 14 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 4 of 13 in this topic. Use this comparison to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 4 of 13

Practice

21 questions

Recall

14 flashcards

⚗️ Half Equations — Must Know!

Electrode Process Half equation What happens
CATHODE (−) Reduction — gain of electrons Al³⁺ + 3e⁻ → Al Aluminium ions gain 3 electrons → molten aluminium metal sinks to the bottom
ANODE (+) Oxidation — loss of electrons 2O²⁻ → O₂ + 4e⁻ Oxide ions lose electrons → oxygen gas; oxygen reacts with hot carbon: C + O₂ → CO₂

Overall equation: 2Al₂O₃ → 4Al + 3O₂

This requires electrical energy — it is NOT a spontaneous reaction.

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Read this section alongside the surrounding pages in Electrolysis of Aluminium. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Electrolysis of Aluminium

Why is aluminium extracted by electrolysis rather than by reduction with carbon?

  • A. Aluminium is less reactive than carbon
  • B. Aluminium is more reactive than carbon
  • C. Aluminium does not form ions
  • D. Carbon reacts with aluminium to form carbides
1 markfoundation

Explain why aluminium is extracted by electrolysis rather than by reduction with carbon.

2 marksstandard

Quick Recall Flashcards

Why do the carbon anodes need replacing regularly?
At 950°C, the oxygen produced at the anode reacts with the hot carbon: C + O₂ → CO₂. The carbon is gradually burned away, so the anodes must be replaced periodically.
What does OIL RIG stand for?
Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons). At the Anode = Oxidation (loss). At the Cathode = Reduction (gain).

21 questions on Electrolysis of Aluminium — practise free

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