Exercise 1 — IGCSE 0653 Mar 2025 Paper 32 Q5
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0.5 (%)
Cambridge IGCSE·Combined Sciences 0653·Chemistry
Electrochemistry
Key knowledge — Electrochemistry
Key facts & rules
- Electrolysis: uses electrical energy to decompose an ionic compound (in solution or molten).
- Electrolyte: ionic compound that conducts electricity when dissolved or molten.
- Cathode (−): positive ions (cations) are attracted here and GAIN electrons (reduction).
- Anode (+): negative ions (anions) are attracted here and LOSE electrons (oxidation).
- Electrolysis of brine (NaCl solution): cathode → hydrogen gas; anode → chlorine gas; NaOH remains.
- Electrolysis of dilute H₂SO₄: cathode → hydrogen gas; anode → oxygen gas.
- Electroplating: object to be plated = cathode; plating metal = anode; solution of plating metal ions = electrolyte.
- Extraction of aluminium: Al₂O₃ dissolved in molten cryolite; cathode → Al; anode → O₂.
IGCSE Chemistry — Electrochemistry
100 Cambridge IGCSE 0653 Combined Sciences past paper questions on electrochemistry, across Theory, Multiple Choice and Alternative to Practical.
About Electrochemistry on IGCSE 0653
Electrolysis uses electrical energy to decompose ionic substances. During electrolysis, cations migrate to the cathode and anions to the anode. Industrial applications include the extraction of aluminium and electroplating.
What's covered:
- Electrolytes and non-electrolytes
- Anode and cathode reactions
- Electrolysis of brine
- Extraction of aluminium
- Electroplating
- Fuel cells
Theory
Electrochemistry — Core3 · Paper 3
Exercise 2 — IGCSE 0653 May/Jun 2024 Paper 32 Q5
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electrolysis (circled)
Exercise 3 — IGCSE 0653 May/Jun 2025 Paper 32 Q5
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first and second boxes ticked
Electrochemistry — Extended9 · Paper 4
Exercise 1 — IGCSE 0653 Mar 2023 Paper 42 Q2
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(positive) anode AND (negative) cathode
Exercise 2 — IGCSE 0653 Mar 2024 Paper 42 Q2
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helium
Exercise 3 — IGCSE 0653 Mar 2024 Paper 42 Q5
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(molten because) ions must, be free to move / be mobile / migrate
Exercise 4 — IGCSE 0653 May/Jun 2023 Paper 41 Q2
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H+
Exercise 5 — IGCSE 0653 May/Jun 2023 Paper 42 Q2
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water
Exercise 6 — IGCSE 0653 May/Jun 2023 Paper 43 Q2
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hydroxide (ions)
Exercise 7 — IGCSE 0653 Oct/Nov 2023 Paper 41 Q2
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does not react / is unreactive
Exercise 8 — IGCSE 0653 Oct/Nov 2023 Paper 43 Q2
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hydrogen H+ AND decreases
Exercise 9 — IGCSE 0653 Oct/Nov 2023 Paper 42 Q8
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Fe2O3 + 3CO → 2Fe + 3CO2
Multiple choice
Electrochemistry — Core MCQ38 · Paper 1
Question 1 — IGCSE 0653 Mar 2024 Paper 12 Q16
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Correct answer: C
Question 2 — IGCSE 0653 Mar 2024 Paper 12 Q17
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Correct answer: D
Question 3 — IGCSE 0653 Mar 2024 Paper 12 Q18
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Correct answer: A
Question 4 — IGCSE 0653 Mar 2024 Paper 12 Q19
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Correct answer: B
Question 5 — IGCSE 0653 May/Jun 2023 Paper 11 Q15
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Correct answer: D
Question 6 — IGCSE 0653 May/Jun 2023 Paper 12 Q15
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Correct answer: D
Question 7 — IGCSE 0653 May/Jun 2023 Paper 11 Q16
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Correct answer: B
Question 8 — IGCSE 0653 May/Jun 2023 Paper 12 Q16
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Correct answer: A
Question 9 — IGCSE 0653 May/Jun 2023 Paper 11 Q17
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Correct answer: C
Question 10 — IGCSE 0653 May/Jun 2023 Paper 12 Q17
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Correct answer: D
Question 11 — IGCSE 0653 May/Jun 2023 Paper 11 Q18
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Correct answer: B
Question 12 — IGCSE 0653 May/Jun 2023 Paper 12 Q18
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Correct answer: B
Question 13 — IGCSE 0653 May/Jun 2024 Paper 11 Q18
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Correct answer: A
Question 14 — IGCSE 0653 May/Jun 2024 Paper 11 Q19
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Correct answer: D
Question 15 — IGCSE 0653 May/Jun 2024 Paper 13 Q19
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Correct answer: A
Question 16 — IGCSE 0653 May/Jun 2024 Paper 11 Q20
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Correct answer: A
Question 17 — IGCSE 0653 May/Jun 2024 Paper 13 Q20
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Correct answer: D
Question 18 — IGCSE 0653 May/Jun 2024 Paper 13 Q21
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Correct answer: C
Question 19 — IGCSE 0653 May/Jun 2024 Paper 12 Q36
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Correct answer: D
Question 20 — IGCSE 0653 May/Jun 2024 Paper 12 Q37
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Correct answer: B
Question 21 — IGCSE 0653 May/Jun 2024 Paper 12 Q38
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Correct answer: D
Question 22 — IGCSE 0653 May/Jun 2024 Paper 12 Q39
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Correct answer: D
Question 23 — IGCSE 0653 May/Jun 2025 Paper 12 Q15
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Correct answer: C
Question 24 — IGCSE 0653 May/Jun 2025 Paper 11 Q16
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Correct answer: A
Question 25 — IGCSE 0653 May/Jun 2025 Paper 12 Q16
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Correct answer: A
Question 26 — IGCSE 0653 May/Jun 2025 Paper 12 Q17
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Correct answer: A
Question 27 — IGCSE 0653 May/Jun 2025 Paper 13 Q17
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Correct answer: C
Question 28 — IGCSE 0653 May/Jun 2025 Paper 12 Q18
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Correct answer: B
Question 29 — IGCSE 0653 May/Jun 2025 Paper 13 Q18
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Correct answer: B
Question 30 — IGCSE 0653 May/Jun 2025 Paper 12 Q19
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Correct answer: A
Question 31 — IGCSE 0653 May/Jun 2025 Paper 13 Q19
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Correct answer: D
Question 32 — IGCSE 0653 May/Jun 2025 Paper 12 Q20
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Correct answer: B
Question 33 — IGCSE 0653 May/Jun 2025 Paper 11 Q23
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Correct answer: C
Question 34 — IGCSE 0653 May/Jun 2025 Paper 11 Q24
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Correct answer: A
Question 35 — IGCSE 0653 May/Jun 2025 Paper 12 Q24
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Correct answer: D
Question 36 — IGCSE 0653 May/Jun 2025 Paper 11 Q25
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Correct answer: B
Question 37 — IGCSE 0653 May/Jun 2025 Paper 12 Q25
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Correct answer: D
Question 38 — IGCSE 0653 May/Jun 2025 Paper 11 Q26
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Correct answer: D
Electrochemistry — Extended MCQ50 · Paper 2
Question 1 — IGCSE 0653 Mar 2024 Paper 22 Q16
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Correct answer: C
Question 2 — IGCSE 0653 Mar 2024 Paper 22 Q17
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Correct answer: C
Question 3 — IGCSE 0653 Mar 2024 Paper 22 Q18
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Correct answer: D
Question 4 — IGCSE 0653 Mar 2024 Paper 22 Q19
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Correct answer: A
Question 5 — IGCSE 0653 Mar 2024 Paper 22 Q22
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Correct answer: A
Question 6 — IGCSE 0653 Mar 2024 Paper 22 Q23
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Correct answer: B
Question 7 — IGCSE 0653 Mar 2024 Paper 22 Q24
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Correct answer: B
Question 8 — IGCSE 0653 May/Jun 2023 Paper 21 Q17
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Correct answer: C
Question 9 — IGCSE 0653 May/Jun 2023 Paper 22 Q17
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Correct answer: B
Question 10 — IGCSE 0653 May/Jun 2023 Paper 21 Q18
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Correct answer: D
Question 11 — IGCSE 0653 May/Jun 2023 Paper 22 Q18
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Correct answer: B
Question 12 — IGCSE 0653 May/Jun 2023 Paper 21 Q19
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Correct answer: B
Question 13 — IGCSE 0653 May/Jun 2023 Paper 22 Q19
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Correct answer: C
Question 14 — IGCSE 0653 May/Jun 2023 Paper 21 Q20
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Correct answer: C
Question 15 — IGCSE 0653 May/Jun 2023 Paper 22 Q20
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Correct answer: B
Question 16 — IGCSE 0653 May/Jun 2023 Paper 21 Q21
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Correct answer: A
Question 17 — IGCSE 0653 May/Jun 2024 Paper 21 Q15
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Correct answer: B
Question 18 — IGCSE 0653 May/Jun 2024 Paper 22 Q15
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Correct answer: A
Question 19 — IGCSE 0653 May/Jun 2024 Paper 21 Q16
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Correct answer: A
Question 20 — IGCSE 0653 May/Jun 2024 Paper 22 Q16
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Correct answer: D
Question 21 — IGCSE 0653 May/Jun 2024 Paper 21 Q17
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Correct answer: D
Question 22 — IGCSE 0653 May/Jun 2024 Paper 22 Q17
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Correct answer: B
Question 23 — IGCSE 0653 May/Jun 2024 Paper 21 Q18
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Correct answer: A
Question 24 — IGCSE 0653 May/Jun 2024 Paper 22 Q18
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Correct answer: A
Question 25 — IGCSE 0653 May/Jun 2024 Paper 23 Q18
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Correct answer: B
Question 26 — IGCSE 0653 May/Jun 2024 Paper 23 Q19
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Correct answer: C
Question 27 — IGCSE 0653 May/Jun 2024 Paper 23 Q20
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Correct answer: A
Question 28 — IGCSE 0653 May/Jun 2024 Paper 23 Q35
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Correct answer: D
Question 29 — IGCSE 0653 May/Jun 2024 Paper 23 Q36
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Correct answer: D
Question 30 — IGCSE 0653 May/Jun 2024 Paper 23 Q37
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Correct answer: D
Question 31 — IGCSE 0653 May/Jun 2024 Paper 23 Q38
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Correct answer: C
Question 32 — IGCSE 0653 May/Jun 2024 Paper 23 Q39
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Correct answer: C
Question 33 — IGCSE 0653 May/Jun 2025 Paper 23 Q16
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Correct answer: D
Question 34 — IGCSE 0653 May/Jun 2025 Paper 21 Q17
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Correct answer: C
Question 35 — IGCSE 0653 May/Jun 2025 Paper 23 Q17
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Correct answer: A
Question 36 — IGCSE 0653 May/Jun 2025 Paper 21 Q18
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Correct answer: C
Question 37 — IGCSE 0653 May/Jun 2025 Paper 23 Q18
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Correct answer: C
Question 38 — IGCSE 0653 May/Jun 2025 Paper 21 Q19
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Correct answer: B
Question 39 — IGCSE 0653 May/Jun 2025 Paper 22 Q26
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Correct answer: D
Question 40 — IGCSE 0653 May/Jun 2025 Paper 22 Q27
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Correct answer: C
Question 41 — IGCSE 0653 May/Jun 2025 Paper 22 Q28
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Correct answer: A
Question 42 — IGCSE 0653 May/Jun 2025 Paper 22 Q29
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Correct answer: B
Question 43 — IGCSE 0653 Oct/Nov 2023 Paper 21 Q16
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Correct answer: A
Question 44 — IGCSE 0653 Oct/Nov 2023 Paper 21 Q17
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Correct answer: C
Question 45 — IGCSE 0653 Oct/Nov 2023 Paper 21 Q18
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Correct answer: B
Question 46 — IGCSE 0653 Oct/Nov 2023 Paper 23 Q22
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Correct answer: A
Question 47 — IGCSE 0653 Oct/Nov 2023 Paper 23 Q23
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Correct answer: A
Question 48 — IGCSE 0653 Oct/Nov 2023 Paper 23 Q24
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Correct answer: C
Question 49 — IGCSE 0653 Oct/Nov 2023 Paper 23 Q25
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Correct answer: B
Question 50 — IGCSE 0653 Oct/Nov 2023 Paper 23 Q26
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Correct answer: C
All Electrochemistry questions in this collection
| Type | Level | Paper | Session | Q# | Marks | Answer / key |
|---|---|---|---|---|---|---|
| MCQ | Core | Paper 12 | Mar 2024 | Q16 | 1 mark | C |
| MCQ | Core | Paper 12 | Mar 2024 | Q17 | 1 mark | D |
| MCQ | Core | Paper 12 | Mar 2024 | Q18 | 1 mark | A |
| MCQ | Core | Paper 12 | Mar 2024 | Q19 | 1 mark | B |
| MCQ | Core | Paper 11 | May/Jun 2023 | Q15 | 1 mark | D |
| MCQ | Core | Paper 12 | May/Jun 2023 | Q15 | 1 mark | D |
| MCQ | Core | Paper 11 | May/Jun 2023 | Q16 | 1 mark | B |
| MCQ | Core | Paper 12 | May/Jun 2023 | Q16 | 1 mark | A |
| MCQ | Core | Paper 11 | May/Jun 2023 | Q17 | 1 mark | C |
| MCQ | Core | Paper 12 | May/Jun 2023 | Q17 | 1 mark | D |
| MCQ | Core | Paper 11 | May/Jun 2023 | Q18 | 1 mark | B |
| MCQ | Core | Paper 12 | May/Jun 2023 | Q18 | 1 mark | B |
| MCQ | Core | Paper 11 | May/Jun 2024 | Q18 | 1 mark | A |
| MCQ | Core | Paper 11 | May/Jun 2024 | Q19 | 1 mark | D |
| MCQ | Core | Paper 13 | May/Jun 2024 | Q19 | 1 mark | A |
| MCQ | Core | Paper 11 | May/Jun 2024 | Q20 | 1 mark | A |
| MCQ | Core | Paper 13 | May/Jun 2024 | Q20 | 1 mark | D |
| MCQ | Core | Paper 13 | May/Jun 2024 | Q21 | 1 mark | C |
| MCQ | Core | Paper 12 | May/Jun 2024 | Q36 | 1 mark | D |
| MCQ | Core | Paper 12 | May/Jun 2024 | Q37 | 1 mark | B |
| MCQ | Core | Paper 12 | May/Jun 2024 | Q38 | 1 mark | D |
| MCQ | Core | Paper 12 | May/Jun 2024 | Q39 | 1 mark | D |
| MCQ | Core | Paper 12 | May/Jun 2025 | Q15 | 1 mark | C |
| MCQ | Core | Paper 11 | May/Jun 2025 | Q16 | 1 mark | A |
| MCQ | Core | Paper 12 | May/Jun 2025 | Q16 | 1 mark | A |
| MCQ | Core | Paper 12 | May/Jun 2025 | Q17 | 1 mark | A |
| MCQ | Core | Paper 13 | May/Jun 2025 | Q17 | 1 mark | C |
| MCQ | Core | Paper 12 | May/Jun 2025 | Q18 | 1 mark | B |
| MCQ | Core | Paper 13 | May/Jun 2025 | Q18 | 1 mark | B |
| MCQ | Core | Paper 12 | May/Jun 2025 | Q19 | 1 mark | A |
| MCQ | Core | Paper 13 | May/Jun 2025 | Q19 | 1 mark | D |
| MCQ | Core | Paper 12 | May/Jun 2025 | Q20 | 1 mark | B |
| MCQ | Core | Paper 11 | May/Jun 2025 | Q23 | 1 mark | C |
| MCQ | Core | Paper 11 | May/Jun 2025 | Q24 | 1 mark | A |
| MCQ | Core | Paper 12 | May/Jun 2025 | Q24 | 1 mark | D |
| MCQ | Core | Paper 11 | May/Jun 2025 | Q25 | 1 mark | B |
| MCQ | Core | Paper 12 | May/Jun 2025 | Q25 | 1 mark | D |
| MCQ | Core | Paper 11 | May/Jun 2025 | Q26 | 1 mark | D |
| MCQ | Extended | Paper 22 | Mar 2024 | Q16 | 1 mark | C |
| MCQ | Extended | Paper 22 | Mar 2024 | Q17 | 1 mark | C |
| MCQ | Extended | Paper 22 | Mar 2024 | Q18 | 1 mark | D |
| MCQ | Extended | Paper 22 | Mar 2024 | Q19 | 1 mark | A |
| MCQ | Extended | Paper 22 | Mar 2024 | Q22 | 1 mark | A |
| MCQ | Extended | Paper 22 | Mar 2024 | Q23 | 1 mark | B |
| MCQ | Extended | Paper 22 | Mar 2024 | Q24 | 1 mark | B |
| MCQ | Extended | Paper 21 | May/Jun 2023 | Q17 | 1 mark | C |
| MCQ | Extended | Paper 22 | May/Jun 2023 | Q17 | 1 mark | B |
| MCQ | Extended | Paper 21 | May/Jun 2023 | Q18 | 1 mark | D |
| MCQ | Extended | Paper 22 | May/Jun 2023 | Q18 | 1 mark | B |
| MCQ | Extended | Paper 21 | May/Jun 2023 | Q19 | 1 mark | B |
| MCQ | Extended | Paper 22 | May/Jun 2023 | Q19 | 1 mark | C |
| MCQ | Extended | Paper 21 | May/Jun 2023 | Q20 | 1 mark | C |
| MCQ | Extended | Paper 22 | May/Jun 2023 | Q20 | 1 mark | B |
| MCQ | Extended | Paper 21 | May/Jun 2023 | Q21 | 1 mark | A |
| MCQ | Extended | Paper 21 | May/Jun 2024 | Q15 | 1 mark | B |
| MCQ | Extended | Paper 22 | May/Jun 2024 | Q15 | 1 mark | A |
| MCQ | Extended | Paper 21 | May/Jun 2024 | Q16 | 1 mark | A |
| MCQ | Extended | Paper 22 | May/Jun 2024 | Q16 | 1 mark | D |
| MCQ | Extended | Paper 21 | May/Jun 2024 | Q17 | 1 mark | D |
| MCQ | Extended | Paper 22 | May/Jun 2024 | Q17 | 1 mark | B |
| MCQ | Extended | Paper 21 | May/Jun 2024 | Q18 | 1 mark | A |
| MCQ | Extended | Paper 22 | May/Jun 2024 | Q18 | 1 mark | A |
| MCQ | Extended | Paper 23 | May/Jun 2024 | Q18 | 1 mark | B |
| MCQ | Extended | Paper 23 | May/Jun 2024 | Q19 | 1 mark | C |
| MCQ | Extended | Paper 23 | May/Jun 2024 | Q20 | 1 mark | A |
| MCQ | Extended | Paper 23 | May/Jun 2024 | Q35 | 1 mark | D |
| MCQ | Extended | Paper 23 | May/Jun 2024 | Q36 | 1 mark | D |
| MCQ | Extended | Paper 23 | May/Jun 2024 | Q37 | 1 mark | D |
| MCQ | Extended | Paper 23 | May/Jun 2024 | Q38 | 1 mark | C |
| MCQ | Extended | Paper 23 | May/Jun 2024 | Q39 | 1 mark | C |
| MCQ | Extended | Paper 23 | May/Jun 2025 | Q16 | 1 mark | D |
| MCQ | Extended | Paper 21 | May/Jun 2025 | Q17 | 1 mark | C |
| MCQ | Extended | Paper 23 | May/Jun 2025 | Q17 | 1 mark | A |
| MCQ | Extended | Paper 21 | May/Jun 2025 | Q18 | 1 mark | C |
| MCQ | Extended | Paper 23 | May/Jun 2025 | Q18 | 1 mark | C |
| MCQ | Extended | Paper 21 | May/Jun 2025 | Q19 | 1 mark | B |
| MCQ | Extended | Paper 22 | May/Jun 2025 | Q26 | 1 mark | D |
| MCQ | Extended | Paper 22 | May/Jun 2025 | Q27 | 1 mark | C |
| MCQ | Extended | Paper 22 | May/Jun 2025 | Q28 | 1 mark | A |
| MCQ | Extended | Paper 22 | May/Jun 2025 | Q29 | 1 mark | B |
| MCQ | Extended | Paper 21 | Oct/Nov 2023 | Q16 | 1 mark | A |
| MCQ | Extended | Paper 21 | Oct/Nov 2023 | Q17 | 1 mark | C |
| MCQ | Extended | Paper 21 | Oct/Nov 2023 | Q18 | 1 mark | B |
| MCQ | Extended | Paper 23 | Oct/Nov 2023 | Q22 | 1 mark | A |
| MCQ | Extended | Paper 23 | Oct/Nov 2023 | Q23 | 1 mark | A |
| MCQ | Extended | Paper 23 | Oct/Nov 2023 | Q24 | 1 mark | C |
| MCQ | Extended | Paper 23 | Oct/Nov 2023 | Q25 | 1 mark | B |
| MCQ | Extended | Paper 23 | Oct/Nov 2023 | Q26 | 1 mark | C |
| Theory | Core | Paper 32 | Mar 2025 | Q5 | 7 marks | 0.5 (%) |
| Theory | Core | Paper 32 | May/Jun 2024 | Q5 | 8 marks | electrolysis (circled) |
| Theory | Core | Paper 32 | May/Jun 2025 | Q5 | 10 marks | first and second boxes ticked |
| Theory | Extended | Paper 42 | Mar 2023 | Q2 | 7 marks | (positive) anode AND (negative) cathode |
| Theory | Extended | Paper 42 | Mar 2024 | Q2 | 9 marks | helium |
| Theory | Extended | Paper 42 | Mar 2024 | Q5 | 8 marks | (molten because) ions must, be free to move / be mobile / migrate |
| Theory | Extended | Paper 41 | May/Jun 2023 | Q2 | 8 marks | H+ |
| Theory | Extended | Paper 42 | May/Jun 2023 | Q2 | 8 marks | water |
| Theory | Extended | Paper 43 | May/Jun 2023 | Q2 | 8 marks | hydroxide (ions) |
| Theory | Extended | Paper 41 | Oct/Nov 2023 | Q2 | 8 marks | does not react / is unreactive |
| Theory | Extended | Paper 43 | Oct/Nov 2023 | Q2 | 9 marks | hydrogen H+ AND decreases |
| Theory | Extended | Paper 42 | Oct/Nov 2023 | Q8 | 9 marks | Fe2O3 + 3CO → 2Fe + 3CO2 |