Redox: past paper questions

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• Question 18May/June 2026, paper 11Multiple choice1 mark

  When heated strongly, silicon(IV) oxide reacts with carbon. $${\mathrm{S}\mathrm{i}\mathrm{O}}_2+2\mathrm{C}\to \mathrm{S}\mathrm{i}+2\mathrm{C}\mathrm{O}$$ Which term describes what happens to silicon(IV) oxide?

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• Question 16Oct/Nov 2025, paper 11Multiple choice1 mark

  Iron(III) chloride, ${\text{FeCl}}_3$, is a brown solid. What is the meaning of (III) in the name?

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• Question 16Oct/Nov 2024, paper 11Multiple choice1 mark

  The equation for the reaction between hydrogen and oxygen is shown. $$2{\text{H}}_2(\text{g})+{\text{O}}_2(\text{g})\to 2{\text{H}}_2\text{O}(\text{g})$$ Which statement explains why this is a redox reaction?

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• Question 15Oct/Nov 2023, paper 11Multiple choice1 mark

  Which equation shows the reduction of copper?

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• Question 19May/June 2026, paper 11Multiple choice1 mark

  Potassium manganate(VII), ${\mathrm{K}\mathrm{M}\mathrm{n}\mathrm{O}}_4$, is a compound with a range of different uses. What does (VII) indicate about this compound?

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• Question 18Oct/Nov 2025, paper 12Multiple choice1 mark

  What is the oxidation number of iron in iron(III) oxide, ${\text{Fe}}_2{\text{O}}_3$?

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• Question 19Oct/Nov 2024, paper 12Multiple choice1 mark

  The equation for the reaction of magnesium with copper(II) oxide is shown. $$\text{Mg}+\text{CuO}\to \text{MgO}+\text{Cu}$$ Which word describes this reaction?

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• Question 17Oct/Nov 2023, paper 12Multiple choice1 mark

  In a blast furnace, iron(III) oxide is converted to iron and carbon monoxide is converted to carbon dioxide. $${\mathrm{F}\mathrm{e}}_2{\mathrm{O}}_3+3\mathrm{C}\mathrm{O}\to 2\mathrm{F}\mathrm{e}+3{\mathrm{C}\mathrm{O}}_2$$ What happens to each of these reactants?

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• Question 19May/June 2026, paper 13Multiple choice1 markHas a diagram

  The equations show two chemical reactions involved in the production of iron from its ore.

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• Question 17Oct/Nov 2025, paper 13Multiple choice1 mark

  Carbon reacts with silver oxide to form carbon dioxide and silver. Which substance is reduced?

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• Question 25Oct/Nov 2024, paper 12Multiple choice1 mark

  Zinc is formed when zinc oxide is heated with carbon. $$\text{zinc oxide}+\text{carbon}\to \text{zinc}+\text{carbon monoxide}$$ Which substance is oxidised in this reaction?

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• Question 16Oct/Nov 2023, paper 13Multiple choice1 mark

  Ethanol can be turned into ethanoic acid by passing it over hot copper(II) oxide. $${\mathrm{C}\mathrm{H}}_3{\mathrm{C}\mathrm{H}}_2\mathrm{O}\mathrm{H}+2\mathrm{C}\mathrm{u}\mathrm{O}\to {\mathrm{C}\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H}+{\mathrm{H}}_2\mathrm{O}+2\mathrm{C}\mathrm{u}$$ What is this type of reaction?

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• Question 17May/June 2026, paper 21Multiple choice1 mark

  In a reaction, element $\text{J}$ acts as an oxidising agent. Which statements about $\text{J}$ are correct?

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• Question 18Oct/Nov 2025, paper 21Multiple choice1 markHas a diagram

  The ionic equation for the redox reaction between acidified manganate(VII) ions and iodide ions is shown.

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• Question 18Oct/Nov 2024, paper 13Multiple choice1 mark

  Which statements about a redox reaction are correct?

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• Question 26May/June 2026, paper 21Multiple choice1 mark

  The equation for the reaction between magnesium and aqueous copper(II) sulfate is shown. $$\text{Mg}+{\text{CuSO}}_4\to \text{Cu}+{\text{MgSO}}_4$$ Which statement is correct?

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• Question 27Oct/Nov 2025, paper 21Multiple choice1 mark

  The equation for the reaction between aluminium and iron(III) oxide is shown. $$2\mathrm{A}\mathrm{l}+\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3\to \mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3+2\mathrm{F}\mathrm{e}$$ Which statement about this reaction is correct?

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• Question 17Oct/Nov 2024, paper 22Multiple choice1 markHas a diagram

  The equation for the reaction of carbon with carbon dioxide is shown. $$\mathrm{C}+{\mathrm{C}\mathrm{O}}_2\to 2\mathrm{C}\mathrm{O}$$ Which row identifies the carbon atom that is reduced and its change in oxidation number?

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• Question 18May/June 2026, paper 22Multiple choice1 markHas a diagram

  The equation represents the reaction between sulfur dioxide and acidified potassium dichromate(VI).

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• Question 19Oct/Nov 2025, paper 22Multiple choice1 mark

  What is the oxidation number of chromium in the ${\text{Cr}}_2{\text{O}}_7^{2-}$ ion?

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• Question 18Oct/Nov 2024, paper 22Multiple choice1 markHas a diagram

  Aqueous iron(II) sulfate is added to acidified potassium manganate(VII). The purple colour of the potassium manganate(VII) disappears. Aqueous potassium iodide is added to acidified potassium dichromate(VI).

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• Question 21May/June 2026, paper 23Multiple choice1 mark

  The ionic equation for the reaction of aqueous iron(II) sulfate with acidified aqueous potassium manganate(VII) is shown.

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• Question 22Oct/Nov 2025, paper 23Multiple choice1 mark

  The equation shows the reaction between copper and concentrated nitric acid. $$\text{Cu}(\text{s})+4{\text{HNO}}_3(\text{aq})\to \text{Cu}({\text{NO}}_3{)}_2(\text{aq})+2{\text{NO}}_2(\text{g})+2{\text{H}}_2\text{O}(\text{l})$$ Which element is reduced in this reaction?

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• Question 19Oct/Nov 2024, paper 23Multiple choice1 mark

  Which statement about reactants in redox reactions is correct?

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• Question 18Oct/Nov 2023, paper 22Multiple choice1 markHas a diagram

  Which row describes what happens to ${\mathrm{F}\mathrm{e}}^{2+}$ ions when they are oxidised?

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• Question 28May/June 2026, paper 23Multiple choice1 mark

  Four mixtures are listed. 1 ${\text{Cu}}^{2+}\text{(aq)}+\text{Ag(s)}$ 2 $\text{Zn(s)}+{\text{Fe}}^{2+}\text{(aq)}$ 3 ${\text{Cu}}^{2+}\text{(aq)}+\text{Mg(s)}$ 4 $\text{Cu(s)}+{\text{Ag}}^{+}\text{(aq)}$ Which mixtures would lead to a reaction?

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• Question 2Oct/Nov 2025, paper 42Structured19 marks

  Iron is extracted from iron ore in a blast furnace. The iron compound in the main iron ore used in the blast furnace is iron(III) oxide. State the name of the main iron ore used in the blast furnace.

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• Question 20Oct/Nov 2024, paper 23Multiple choice1 markHas a diagram

  Aluminium is extracted from aluminium oxide by electrolysis. The ionic half-equation for the reaction at one of the electrodes is shown.

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• Question 4Oct/Nov 2025, paper 42Structured15 marks

  Nitric acid, ${\text{HNO}}_3$, and sulfuric acid, ${\text{H}}_2{\text{SO}}_4$, are strong acids. Ethanoic acid, ${\text{CH}}_3\text{COOH}$, is a weak acid. One mole of each acid is added separately to $1000{\text{cm}}^3$ of distilled water to form a dilute solution.

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• Question 24Oct/Nov 2024, paper 23Multiple choice1 mark

  Acidified potassium dichromate(VI), ${\text{K}}_2{\text{Cr}}_2{\text{O}}_7$, is used to oxidise ethanol, ${\text{C}}_2{\text{H}}_5\text{OH}$. The ionic equation for the reaction is shown.

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