plumiHomogeneous catalysts and autocatalysis: Edexcel International A Level Chemistry questions
Edexcel International A Level Chemistry past-paper questions on 17.3.2 Homogeneous catalysts and autocatalysis, 2019–2025, with mark schemes and examiner’s reports where available.
All papers
All years
Loading the question…
Open the full PDFYour answerQ4(a)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFYour answerQ4(b)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFYour answerLoading the question…
Open the full PDFQ3(a)(iv)
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 PDFQ3(b)(ii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ3(b)(iii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFLoading the question…
Open the full PDFYour answerQ19(b)(i)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ19(b)(ii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFLoading the question…
Open the full PDFYour answerQ20(d)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFLoading the question…
Open the full PDFYour answerQ1(a)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFYour answerQ1(b)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFYour answerLoading the question…
Open the full PDFYour answerLoading the question…
Open the full PDFYour answerQ21(e)(i)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ21(e)(ii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDF
All 23 questions on Homogeneous catalysts and autocatalysis, as a list
- June 2025 (A), Unit 5, Q9 (1 mark): 2– , is mixed with 9 An acidified solution, containing tartrate ions, C4H4O6 hydrogen peroxide solution. When pink cobalt(II) chloride solution is added to the
- October 2024, Unit 5, Q4(a) (1 mark): What is the best explanation for the high activation energy of this reaction? (1) A the peroxodisulfate ion is a weak oxidising agent B the iodide ion is a weak
- October 2024, Unit 5, Q4(b) (1 mark): Which property of iron(II) ions enables them to function as a catalyst for this reaction? (1) A iron(II) ions can be easily reduced to metallic iron B iron(II)
- October 2024, Unit 5, Q14 (1 mark): The formation of carbon dioxide from the reaction between manganate(VII) ions and ethanedioate ions is autocatalysed by manganese(II) ions. The equation for thi
- October 2024, Unit 6, Q3(a)(iv) (3 marks): Suggest why, in Step 2, the temperature of the mixture at the start should be 60°C but no further warming is needed after a small quantity of the potassium mang
- June 2024, Unit 6, Q3(b)(i) (3 marks): Plot a graph of volume of sodium thiosulfate against time. (3)
- June 2024, Unit 6, Q3(b)(ii) (1 mark): Describe how the rate of reaction changes during the reaction. (1)
- June 2024, Unit 6, Q3(b)(iii) (3 marks): Explain why the rate of reaction changes in this way. (3)
- October 2023, Unit 5, Q6 (1 mark): Acidified manganate(VII) ions react with ethanedioate ions. 2− → 2Mn2+ + 8H2O + 10CO2 2MnO4 − + 16H+ + 5C2O4 The rate of this reaction increases then decreases.
- October 2023, Unit 5, Q19(b)(i) (1 mark): Give a reason why the activation energy for this reaction is high in the absence of a catalyst. (1)
- October 2023, Unit 5, Q19(b)(ii) (2 marks): Write the ionic equations for the reactions that occur when the catalyst of Fe2+ ions is added. State symbols are not required. (2)
- January 2023, Unit 5, Q7 (1 mark): Persulfate ions react slowly with iodide ions at room temperature unless a catalyst of Fe2+ or Fe3+ is added to the reaction mixture. 2–(aq) + 2I–(aq) → 2SO4 2–
- January 2023, Unit 5, Q20(d) (3 marks): Manganate(VII) ions react with ethanedioate ions in acidic solution. 2MnO4 –(aq) + 16H+(aq) + 5C2O4 2–(aq) → 2Mn2+(aq) + 8H2O(l) + 10CO2(g) Two experiments were
- October 2022, Unit 5, Q9 (1 mark): The sequence shown is the mechanism for a reaction in aqueous solution. Step 1 Ag+ + Ce4+ → Ag2+ + Ce3+ Step 2 Ti+ + Ag2+ → Ti2+ + Ag+ Step 3 Ti2+ + Ce4+ → Ti3+
- June 2022, Unit 5, Q1(a) (1 mark): Some standard electrode potentials are shown. Right-hand electrode system E / V Cu2+ + e− Cu+ +0.15 I2 + 2e− 2I− +0.54 Fe3+ + e− Fe2+ +0.77 Cl2 + 2e− 2C
- June 2022, Unit 5, Q1(b) (1 mark): Which term best describes the type of catalyst for the reaction in (a)? (1) A autocatalyst B biocatalyst C heterogeneous D homogeneous
- October 2021, Unit 5, Q9 (1 mark): The reaction of ethanedioate ions, C2O 4 2– , with manganate(VII) ions, MnO 4 – , in acidic solution involves autocatalysis. 2– → 2Mn2+ + 10CO2 + 8H2O 2MnO 4 –
- October 2021, Unit 5, Q10 (1 mark): Iodide ions, I–, are oxidised by peroxodisulfate(VI) ions, S2O 8 2– . 2I–(aq) + S2O 8 2–(aq) → I2(aq) + 2SO 4 2–(aq) Which of the following statements is true o
- June 2021, Unit 5, Q21(e)(i) (1 mark): State why the catalyst is described as ‘homogeneous’. (1)
- June 2021, Unit 5, Q21(e)(ii) (2 marks): Write two equations to show how iron(II) ions catalyse this oxidation. State symbols are not required. (2)
- June 2021, Unit 5, Q21(e)(iii) (1 mark): Suggest how iron(II) ions lower the activation energy of this reaction. (1)
- January 2021, Unit 5, Q9 (1 mark): Iodide ions are oxidised by peroxodisulfate ions in aqueous solution. 2I− + S2O2− → I2 + 2SO2− 8 4 This reaction is catalysed by adding Fe2+ ions to the solutio
- October 2020, Unit 5, Q24(c) (6 marks): Transition metals, their compounds and their ions can act as heterogeneous and homogeneous catalysts. Compare and contrast these two types of catalytic behaviou
Questions, mark schemes and examiner’s reports are © Pearson Edexcel, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? Edexcel International A Level Chemistry past papers.
The Plumi iPad app also offers exam-style questions with AI feedback on your handwritten working.