plumiOxidising agents and redox equations: OCR A‑Level Chemistry A questions
OCR A-Level Chemistry A past-paper questions on 5.2.3.1 Oxidising agents and redox equations, 2016–2025, with mark schemes and examiner’s reports where available.
All papers
All years
Loading the question…
Open the full PDFYour answerQ4(a)(ii)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ4(a)(iii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ3(b)(i)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ22(d)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ6(c)(i)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ6(c)(ii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ2(b)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ2(c)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFLoading the question…
Open the full PDFYour answerLoading the question…
Open the full PDFYour answerQ5(a)(i)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFLoading the question…
Open the full PDFYour answerQ18(b)(iii)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ6(a)(iv)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ21(c)(i)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ2(b)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ22(b)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDF
All 18 questions on Oxidising agents and redox equations, as a list
- June 2025, Paper 1, Q11 (1 mark): Two redox systems are shown below. Mg2+(aq) + 2e– E ɵ= – 2.37 V Mg(s) Pb2+(aq) + 2e– E ɵ = – 0.13 V Pb(s) Which species is the strongest reducing agent? Mg2+(aq
- June 2025, Paper 3, Q4(a)(ii) (7 marks): Complete the flowchart by adding formulae in the boxes. white precipitate white precipitate Ag+(aq) Ba2+(aq) acidic solution containing three ions Cl2(aq)/H2O(I
- June 2025, Paper 3, Q4(a)(iii) (2 marks): Construct an ionic equation for the reaction of SO3 [2]
- June 2024, Paper 3, Q3(b)(i) (2 marks): In the titration, both iron(II) ions and ethanedioate, C2O4 Construct half-equations for the oxidation of iron(II) and ethanedioate ions. Oxidation of iron(II)
- June 2023, Paper 1, Q22(d) (2 marks): An acidified solution containing Cr2O7 reaction to form a solution containing Cr3+ ions and VO2 + ions. Construct the overall equation for this reaction. [2]
- June 2023, Paper 3, Q6(c)(i) (1 mark): Balance the half-equation for the oxidation process in this reaction. H+ + AuCl4 – + e– Au + HCl [1]
- June 2023, Paper 3, Q6(c)(ii) (3 marks): In the reduction process in this reaction, HNO3 and H+ react together to form 2 oxides: X (Mr = 30) and Z (Mr = 18). Determine the formulae of X and Z and write
- June 2022, Paper 3, Q2(b) (5 marks): A student analyses the redox reactions shown below. State symbols have been omitted. CH3CHO + 2H+ + 2e– E ө = –0.197 V C2H5OH 2– + 14H+ + 6e– 2Cr3+ + 7H2O E ө =
- June 2022, Paper 3, Q2(c) (2 marks): A student bubbles hydrogen sulfide gas, H2S(g), through an acidified solution containing –(aq). manganate(VII) ions, MnO4 A redox reaction takes place, forming
- November 2021, Paper 1, Q3 (1 mark): The unbalanced equation for the reaction of silver with concentrated nitric acid is shown below. –(aq) + ….. H+(aq) → ….. Ag+(aq) + .…. NO(g) + ..… H2O(l) ….. A
- November 2021, Paper 1, Q12 (1 mark): Two redox systems are shown below. Fe2+(aq) + 2e– Eo– = –0.44 V Fe(s) Cu2+(aq) + 2e– Eo– = +0.34 V Cu(s) Which species in the two redox systems is the strongest
- November 2021, Paper 3, Q5(a)(i) (2 marks): This is a redox reaction. Write half-equations for the reduction and oxidation processes that take place. Reduction Oxidation [2]
- November 2020, Paper 1, Q12 (1 mark): Iodide ions, I−(aq), react with MnO4 −(aq). The unbalanced equation is shown below. I−(aq) + MnO4 −(aq) + H2O(l) IO−(aq) + MnO2(s) + OH−(aq) What is the ratio o
- June 2019, Paper 1, Q18(b)(iii) (1 mark): Construct an equation for the first colour change from blue to green. [1]
- June 2019, Paper 3, Q6(a)(iv) (2 marks): Construct an equation for the reaction of H2S(g) with H+(aq)/MnO4 −(aq). [2]
- June 2018, Paper 1, Q21(c)(i) (1 mark): Write the overall equation for the oxidation of Fe2+ by acidified H2O2. [1]
- June 2018, Paper 3, Q2(b) (2 marks): Hydrogen peroxide can act as an oxidising agent or as a reducing agent. Some standard electrode potentials are shown below. 2H+(aq) + O2(g) + 2e– E o = +0.68 V
- June 2017, Paper 1, Q22(b) (2 marks): In Table 22.1, what is the strongest reducing agent and the strongest oxidising agent? Strongest reducing agent Strongest oxidising agent [2]
Questions, mark schemes and examiner’s reports are © OCR, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? OCR A-Level Chemistry A past papers, or our free OCR-style practice pack.
The Plumi iPad app also offers exam-style questions with AI feedback on your handwritten working.