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Redox Chemistry

Track electrons through reactions, electrolysis and electricity-producing cells.

O-Level 6092 (2026) / SEC G3 K324 (2027)

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6 topics

  1. Recognise oxidation and reduction

    Use the model that makes the electron change easiest to see.

  2. Identify the agent from what it does

    The oxidising agent is itself reduced.

  3. Electrolysis of a molten compound

    A power supply forces chemical change using mobile ions.

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  4. Aqueous electrolysis: more than one possible ion

    Water introduces competing products.

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  5. Make the electrodes part of the design

    Copper electrodes behave differently from inert ones.

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  6. Use a reaction to generate electricity

    A simple cell converts chemical energy into electrical energy.

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Scope and references

Learning outcomes and sources

7. Redox Chemistry (6092 / K324). Use the outcome map to find the explanation for a particular syllabus requirement.

See the learning outcome map

  1. 7.1(a) Define oxygen/hydrogen redox

    • Oxygen gain/loss
    • Hydrogen loss/gain

    Recognise oxidation and reduction

  2. 7.1(b) Define electron/oxidation-state redox

    • Electron loss/gain
    • Oxidation-state increase/decrease

    Recognise oxidation and reduction

  3. 7.1(c) Identify redox reactions

    • Apply all three descriptive models
    • Distinguish non-redox reactions

    Recognise oxidation and reduction

  4. 7.1(d) Test redox agents

    • KI to brown iodine
    • Acidified KMnO4 purple to colourless

    Identify the agent from what it does

  5. 7.2(a) Explain electrolysis

    • Molten/aqueous ionic electrolytes
    • Chemical changes at electrodes

    Electrolysis of a molten compound

  6. 7.2(b) Use electrolysis as ionic evidence

    • Fixed ions in solids
    • Mobile ions in liquids/solutions

    Electrolysis of a molten compound

  7. 7.2(c) Explain molten NaCl electrolysis

    • Ion movement
    • Sodium and chlorine products
    • Inert electrodes

    Electrolysis of a molten compound

  8. 7.2(d) Predict molten binary products

    • Metal and non-metal products
    • Inert electrodes

    Electrolysis of a molten compound

  9. 7.2(e) Apply selective discharge

    • Cations and reactivity
    • Halides, hydroxide, sulfate
    • Copper sulfate and dilute/concentrated NaCl
    • Inert electrodes

    Aqueous electrolysis: more than one possible ion

  10. 7.2(f) Predict aqueous products

    • Use concentration, ions and electrode information

    Aqueous electrolysis: more than one possible ion

  11. 7.2(g) Construct electrode equations

    • Atoms and charge balanced
    • Relevant state symbols

    Electrolysis of a molten compoundAqueous electrolysis: more than one possible ion

  12. 7.2(h) Explain copper purification

    • Copper sulfate electrolyte
    • Copper electrodes
    • No technical detail required

    Make the electrodes part of the design

  13. 7.2(i) Explain electroplating

    • Copper plating setup
    • A practical use

    Make the electrodes part of the design

  14. 7.2(j) Explain simple cells

    • Two electrodes in electrolyte
    • Reactivity and electron transfer

    Use a reaction to generate electricity

  15. 7.2(k) Describe hydrogen fuel cells

    • Hydrogen from water/hydrocarbons
    • Oxygen reaction generates electricity
    • No construction detail

    Use a reaction to generate electricity