Redox: past paper questions
Real questions on redox
The newest 20 of 127 written questions. Open one to see it on the real paper.
- 0971/32 · May/June 2026 · Q6c(i)[2]
Nickel reacts with oxygen to form nickel(II) oxide. Complete the symbol equation for this reaction.
See it on the paper → - 0971/42 · May/June 2026 · Q4c(i)[1]
Explain why this is not a redox reaction.
See it on the paper → - 0971/42 · May/June 2026 · Q5b(i)[2]
(i) State the colour and give the name of the precipitate formed when NH.,(aq) is added to Cr3*(aq) ions. Colour precipitate .......... Name precipitate 02 ..........
See it on the paper → - 0971/42 · May/June 2026 · Q5b(ii)[2]
When a few drops of NH,(aq) are added to Zn?*(aq) a white precipitate forms. When a few drops of Zn2*(aq) are added to NH,(aq) no precipitate forms. Explain these observations.
See it on the paper → - 0971/42 · May/June 2026 · Q5c(ii)[3]
Figure 5.1 shows an incomplete reaction profile diagram for the forward reaction. A energy - > progress of reaction Figure 5.1 On Figure 5.1: * — write the formulas of the reactants and the products ° draw an arrow, labelled E,, to show the activation energy ¢ draw an arrow, labelled AH, to show the enthalpy change.
See it on the paper → - 0971/42 · May/June 2026 · Q6e(i)[1]
Name the acidified aqueous oxidising agent used in method 1.
See it on the paper → - 0971/32 · October/November 2025 · Q6a(iii)[1]
An equation for the reduction of iron( III ) oxide using carbon is shown. 2Fe 2 O 3 + 3C 4Fe + 3CO 2 Explain how this equation shows that iron( III ) oxide is reduced.
See it on the paper → - 0971/32 · October/November 2025 · Q6b(ii)[2]
Name the two substances required for iron to rust. and (ii)
See it on the paper → - 0971/32 · October/November 2025 · Q6b(iii)[2]
State the chemical name for rust.
See it on the paper → - 0971/32 · October/November 2025 · Q6c(ii)[2]
Complete the word equation for the reaction of strontium with hydrochloric acid. strontium + hydrochloric +
See it on the paper → - 0971/42 · October/November 2025 · Q2a(iv)[2]
Write a symbol equation for the reduction of iron( III ) oxide by the gaseous reducing agent in (a)(iii).
See it on the paper → - 0971/42 · October/November 2025 · Q2a(v)[2]
The main impurity in iron ore is silicon( IV ) oxide. Write two symbol equations to show the role of limestone in removing silicon( IV ) oxide from iron ore.
See it on the paper → - 0971/42 · October/November 2025 · Q2d(i)[2]
Define the term oxidising agent.
See it on the paper → - 0971/42 · October/November 2025 · Q2d(ii)[1]
Explain why the conversion of Fe 2+ ions to Fe 3+ ions is described as oxidation.
See it on the paper → - 0971/42 · October/November 2025 · Q2d(iii)[1]
The oxidising agent for the conversion of Fe 2+ ions to Fe 3+ ions is aqueous potassium manganate( VII ). State one condition needed for the oxidation to take place.
See it on the paper → - 0971/42 · October/November 2025 · Q2e[1]
Iodide ions, I – , reduce Fe 3+ ions to Fe 2+ ions in aqueous solution. Suggest the identity of the other product formed in this reaction.
See it on the paper → - 0971/42 · October/November 2025 · Q6d(ii)[1]
Suggest a suitable catalyst for this reaction.
See it on the paper → - 0971/31 · May/June 2025 · Q3b(iii)[2]
Sulfur dioxide reacts with hydrogen sulfide. Complete the symbol equation for this reaction. SO 2 + 2H 2 S S + H 2 O
See it on the paper → - 0971/41 · May/June 2025 · Q3c(iv)[1]
Name a substance, other than copper( II ) carbonate, that can be added to dilute sulfuric acid to produce aqueous copper( II ) sulfate.
See it on the paper → - 0971/41 · May/June 2025 · Q4c(ii)[2]
Give the oxidation number of nitrogen in: • NH
See it on the paper →
What examiners said
Most candidates balanced the hydrogen atoms. Many appeared to miss the three sulfur atoms on the left-hand side of the equation.
— Examiner report, May/June 2025, 0971/31 Q3(b)(iii) (Cambridge)
Large numbers of answers named salts, usually copper chloride or copper nitrate, rather than the required bases.
— Examiner report, May/June 2025, 0971/41 Q3(c)(iv) (Cambridge)
Candidates found this question very challenging. Oxidation numbers without a sign were commonly seen. Candidates should remember to write the sign before the number (e.g., –3) as opposed to the number before the sign (e.g., 3–).
— Examiner report, May/June 2025, 0971/41 Q4(c)(ii) (Cambridge)
Past papers, syllabus and examiner reports © UCLES (Cambridge University Press & Assessment). Questions are matched to topics from the official syllabus. AssessPro is independent and not endorsed by Cambridge.