plumiTitration curves and indicators: Edexcel International A Level Chemistry questions
Every Edexcel International A Level Chemistry exam question on Titration curves and indicators (specification points 14.15–14.16), 2019–2025, with its mark scheme and examiner’s report.
Paper
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Calculations
Q12(a)
The whole paper ↗Your answerQ12(b)
The whole paper ↗Your answerQ17(d)
The whole paper ↗Q2(b)
The whole paper ↗Q20(d)(i)
The whole paper ↗Q20(d)(ii)
The whole paper ↗Q20(d)(iii)
The whole paper ↗- Your answer
- Your answer
- Your answer
Q19(b)
The whole paper ↗Q19(c)(i)
The whole paper ↗Q19(c)(ii)
The whole paper ↗Q19(c)(iii)
The whole paper ↗Q18(a)(iii)
The whole paper ↗Q18(a)(iv)
The whole paper ↗Q18(b)
The whole paper ↗Q18(c)(i)
The whole paper ↗Q18(c)(ii)
The whole paper ↗Q13(a)
The whole paper ↗Your answer
All 43 questions on Titration curves and indicators, as a list
- June 2025, Unit 4, Q12(a) (1 mark): Which curve is produced by adding ammonia to 25 cm3 of hydrochloric acid? (1) A Curve 1 B Curve 2 C Curve 3 D Curve 4
- June 2025, Unit 4, Q12(b) (1 mark): Which of these indicators would be most suitable to determine the end-point for the titration that gives Curve 4? (1) Indicator pH range A congo red 3.0–5.0 B b
- June 2025, Unit 4, Q17(d) (3 marks): A type of bubble bath contains a weak acid and the indicator bromocresol green. The bubble bath is initially yellow but when diluted with bath water, its colour
- June 2025, Unit 6, Q2(b) (2 marks): Give the name of a suitable indicator to use in Step 4, including the expected colour change at the end-point. (2) Name of indicator Colour change from to
- January 2025, Unit 4, Q20(d)(i) (2 marks): A student sketched a curve to show the changing pH during the titration. 14 13 12 11 10 9 8 pH 7 6 5 4 3 2 1 0 10 20 30 40 50 60 Volume of NaOH(aq) added / cm3
- January 2025, Unit 4, Q20(d)(ii) (1 mark): Suggest a difficulty that would occur if both indicators were present in the same mixture. (1)
- January 2025, Unit 4, Q20(d)(iii) (5 marks): Determine, by using the graph, the two Ka values for oxalic acid. You must show your working on the graph. (5)
- October 2024, Unit 4, Q4 (1 mark): A titration curve for the titration of an acid with a strong base is shown. pH Volume of base What could be the formula of the acid? A HX B HX2 C H2X D H3X
- October 2024, Unit 4, Q6 (1 mark): Which indicator can be used to show the end‑point of a titration between hydrochloric acid, HCl(aq), and ammonia solution, NH3(aq)? A universal indicator B phen
- October 2024, Unit 4, Q7 (1 mark): Phenolphthalein is a very weak acid and it forms a colourless solution under acidic conditions. Sodium hydroxide is titrated against hydrochloric acid using phe
- June 2024, Unit 4, Q19(b) (3 marks): 4‑Hydroxybenzoic acid, HOC6H4COOH, is a diprotic acid, which dissociates in two stages. Each stage has a different pKa value. Stage 1 HOC6H4COOH H+ + HOC6H4CO
- January 2024, Unit 4, Q19(c)(i) (2 marks): Calculate the pH at the point in the titration where half the acid has been neutralised. You must show your working. (2)
- January 2024, Unit 4, Q19(c)(ii) (3 marks): Sketch the titration curve showing the change in pH when 50 cm3 of 0.500 mol dm–3 sodium hydroxide is added to 25.0 cm3 of propanoic acid of the same concentrat
- January 2024, Unit 4, Q19(c)(iii) (2 marks): Suggest a suitable indicator for this titration. Justify your choice by referring to your titration curve in (c)(ii). Use the Data Booklet. (2)
- October 2023, Unit 4, Q18(a)(iii) (2 marks): The student deduced that the neutralisation point of the graph at Key point 3 would be at 30 cm3. Use a calculation to justify the student’s deduction. (2)
- October 2023, Unit 4, Q18(a)(iv) (1 mark): The student deduced that when equal amounts of pentanoic acid and potassium hydroxide have been mixed at Key point 3, the pH would be greater than 7. Justify th
- October 2023, Unit 4, Q18(b) (3 marks): The student then completed the sketch graph by linking these four points to show how the pH would change as potassium hydroxide was added. 14 13 12 Key point 4
- October 2023, Unit 4, Q18(c)(i) (3 marks): The student carried out the titration using methyl orange as an indicator. The experiment did not give a satisfactory colour change at the neutralisation point,
- October 2023, Unit 4, Q18(c)(ii) (2 marks): The student found a bottle labelled ‘Acid‑base indicator solution’ in the store cupboard. The student, having checked with the teacher, used this as the indicat
- June 2023, Unit 4, Q13(a) (1 mark): Which indicators could be used for this titration? Use your Data Booklet. (1) A bromocresol green, methyl red and phenolphthalein B bromothymol blue, phenol red
- June 2023, Unit 4, Q13(b) (1 mark): Which acid and base could produce this curve? (1) A CH3COOH and NaOH B CH3COOH and NH3 C HCl and NaOH D HCl and NH3
- June 2023, Unit 4, Q14(a) (1 mark): Which could be the titration curve when sodium hydroxide is added to maleic acid? (1) 14 12 10 8 pH 6 A 4 2 0 0 20 40 60 80 Volume of NaOH / cm3 14 12 10 8 pH 6
- June 2023, Unit 4, Q22(d)(ii) (1 mark): Use the graph to estimate the pH of the salt formed when Tris is neutralised with chloroethanoic acid. (1)
- January 2023, Unit 4, Q21(b)(i) (2 marks): Explain why phenol red is an appropriate indicator for this titration. Refer to the titration curve and the Data Booklet. (2)
- January 2023, Unit 4, Q21(b)(ii) (5 marks): Calculate the pH of the titration mixture after the addition of 35.0 cm3 of sodium hydroxide solution. The value required cannot be obtained from the titration
- October 2022, Unit 4, Q10 (1 mark): Which of these indicators is most suitable for the titration of ammonia solution with hydrochloric acid? A methyl violet (pKin = 0.8) B bromocresol green (pKin
- June 2022, Unit 4, Q9(a) (1 mark): Which titration would produce this curve? (1) A ethanoic acid added to sodium hydroxide B hydrochloric acid added to sodium hydroxide C ethanoic acid added to a
- June 2022, Unit 4, Q9(b) (1 mark): Which indicator would be most suitable for this titration? (1) Indicator pH range A malachite green 0.2–1.8 B methyl yellow 2.9–4.0 C methyl red 4.2–6.3 D thymo
- June 2022, Unit 4, Q19(a)(i) (1 mark): Complete the equation for the reaction taking place in this titration. State symbols are not required. (1) HCOOH +
- June 2022, Unit 4, Q19(a)(ii) (2 marks): Calculate the concentration of the potassium hydroxide solution, using your equation in (i) and the titration curve. (2)
- June 2022, Unit 4, Q19(a)(iii) (3 marks): Use the titration curve to determine a value for the acid dissociation constant, Ka , of methanoic acid. (3)
- January 2022, Unit 4, Q5 (1 mark): An example of a diprotic acid is cis‑butenedioic acid. Titration of this acid using sodium hydroxide solution gave the titration curve shown. 14 12 10 8 pH 6 4
- October 2021, Unit 4, Q20(c) (3 marks): The titration curve obtained from the addition of sodium hydroxide solution to a weak acid is shown. The equivalence point (E) of this titration occurred at pH
- June 2021, Unit 4, Q4(a) (1 mark): Which acidic solution was used in the titration? (1) A 0.1 mol dm–3 CH3COOH B 1.0 mol dm–3 CH3COOH C 0.1 mol dm–3 HCl D 1.0 mol dm–3 HCl
- June 2021, Unit 4, Q4(b) (1 mark): Which basic solution was used in the titration? (1) A NH3 B LiOH C Ba(OH)2 D NaOH
- June 2021, Unit 4, Q4(c) (1 mark): A student suggested five indicators that might be used in this titration: thymol blue methyl orange bromophenol blue bromocresol green phenolphthalein How many
- January 2021, Unit 4, Q10(b) (1 mark): Which of these is the best indicator to use in this titration? [Refer to the Data Booklet] (1) A methyl red B phenol red C phenolphthalein D thymol blue
- January 2021, Unit 4, Q11 (1 mark): A diprotic acid, H2A, was titrated with sodium hydroxide solution. H2A(aq) + 2NaOH(aq) o Na2A(aq) + 2H2O(l) A 25.0 cm3 portion of 0.100 mol dm−3 sodium hydroxid
- October 2020, Unit 4, Q9(a) (1 mark): Which graph has ethanoic acid as one of the reactants? (1) A Graph 1 B Graph 2 C Graph 3 D Graph 4
- October 2020, Unit 4, Q9(b) (1 mark): Which graph shows a solution that has an acidic pH at the end-point? (1) A Graph 1 B Graph 2 C Graph 3 D Graph 4
- October 2020, Unit 4, Q9(c) (1 mark): Which indicator is suitable for the titration shown in Graph 3? Use your Data Booklet. (1) A bromocresol green B bromothymol blue C phenol red D thymol blue (ac
- January 2020, Unit 4, Q11 (1 mark): Which two solutions, both of concentration 0.10 mol dm–3, have been used to produce this titration curve? 14 pH 7 0 Volume of alkali added A HCl(aq) and KOH(aq)
- January 2020, Unit 4, Q20(a)(iv) (2 marks): Two indicators, methyl orange and phenolphthalein, were available for this titration. Student A thought only methyl orange could be used. Student B thought only
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