Acid–base titrations: past paper questions
Real questions on acid–base titrations
The newest 20 of 26 written questions. Open one to see it on the real paper.
- 5070/41 · May/June 2025 · Q2b(i)[3]
Complete Table 2.1 by: • • • writing the initial and final readings for titration 1 calculating the volume of NaOH used in each titration ticking (3) the best titration results. Table 2.1 titration 1 titration 2 titration 3 final burette reading / cm 3 15.4 30.8 initial burette reading / cm 3 0.2 15.4 volume used / cm...
See it on the paper → - 5070/41 · May/June 2025 · Q2b(ii)[1]
Use the best titration results (3) to calculate the average volume of NaOH used. average volume cm 3
See it on the paper → - 5070/41 · May/June 2025 · Q2c[1]
The acid used in (a) to prepare mixture B is in excess. Use your answer to (b)(ii) to calculate the number of moles of 0.100 mol / dm 3 NaOH that react with 25.0 cm 3 of B. number of moles
See it on the paper → - 5070/41 · May/June 2025 · Q2d[1]
Calculate the number of moles of NaOH that react with 100 cm 3 of B. number of moles
See it on the paper → - 5070/41 · May/June 2025 · Q2e[1]
The answer to (d) is equal to the number of moles of HCl that remain in the beaker after the acid reacts with the calcium carbonate in the sample of A. Use your answers to (a) and (d) to calculate the number of moles of HCl that react with the calcium carbonate in the sample of A. number of moles
See it on the paper → - 5070/42 · October/November 2024 · Q2h[1]
State why the HCl (aq) is added drop by drop near the end-point.
See it on the paper → - 5070/42 · May/June 2024 · Q3a(i)[1]
The student leaves a wooden splint with one end dipped into R for ten minutes. The student then places the damp end of the wooden splint into the flame of a Bunsen burner with the air hole open. The student concludes that R contains sodium ions. State the observation which allows the student to make this conclusion.
See it on the paper → - 5070/42 · May/June 2024 · Q3a(ii)[1]
Explain why the air hole on the Bunsen burner must be open when doing this flame test.
See it on the paper → - 5070/42 · May/June 2024 · Q3b(i)[2]
The student adds dilute nitric acid to R. The student observes effervescence of a colourless gas which turns limewater milky. State the conclusions from these observations.
See it on the paper → - 5070/42 · May/June 2024 · Q3b(ii)[1]
The student adds aqueous barium nitrate to some of the mixture from (b)(i). The student concludes that R contains sulfate ions. State the observation which allows the student to make this conclusion.
See it on the paper → - 5070/42 · May/June 2024 · Q3b(iii)[1]
The student adds aqueous silver nitrate to some of the mixture from (b)(i). The student observes a colourless solution. State a conclusion from this observation.
See it on the paper → - 5070/42 · May/June 2024 · Q3b(iv)[2]
The student adds aqueous sodium hydroxide to R and warms the mixture. Describe a test and observation to show that R does not contain ammonium ions. test observation
See it on the paper → - 5070/42 · May/June 2024 · Q3d[2]
The student tests a different solution, P, and finds it difficult to decide whether the solution contains chloride ions or bromide ions. The student also has aqueous potassium chloride and aqueous potassium bromide. Suggest how the student could use the aqueous potassium chloride and aqueous potassium bromide to make i...
See it on the paper → - 5070/42 · May/June 2024 · Q3e[2]
The student adds dilute hydrochloric acid to another solution and a gas is produced. The gas is passed through limewater. Describe how the gas can be passed through limewater. You may draw a labelled diagram to help answer the question. Question 4 starts on page 12
See it on the paper → - 5070/41 · May/June 2023 · Q2g[2]
Suggest why the conical flask is rinsed with distilled water and not 0.400 mol / dm 3 aqueous sodium hydroxide between titrations.
See it on the paper → - 5070/41 · May/June 2023 · Q2h[1]
Some vinegars are brown rather than colourless. Suggest why this titration method would not be suitable for finding the concentration of ethanoic acid in brown vinegar.
See it on the paper → - 5070/41 · May/June 2023 · Q4[2]
Flame test on W. (i) no colour is observed The student correctly concludes that ammonia is formed in test 1. Describe what else the student must have done to reach this conclusion. (ii) State why the student cannot identify the anion in W from the observation in test 3. (iii) State how the tests and observations show t...
See it on the paper → - 5070/21 · May/June 2020 · Q5b[1]
Use the data in the table to state the volume of dilute HCl that just neutralises all of the sample of Ba(OH) 2 (aq). volume of dilute HCl cm 3
See it on the paper → - 5070/21 · May/June 2020 · Q5c[3]
Use your answer to (b) to calculate the concentration, in mol / dm 3 , of the dilute HCl. concentration of dilute HCl mol / dm 3
See it on the paper → - 5070/41 · May/June 2020 · Q2a[3]
Use the information in the diagrams to complete the results table. titration number 1 2 3 final reading / cm 3 initial reading / cm 3 volume used / cm 3
See it on the paper →
What examiners said
Most candidates recognised that if the flask was rinsed with some sodium hydroxide, that some may remain in the flask. Only a minority of candidates then took this further and stated that, if more sodium hydroxide was in the flask, then more ethanoic acid would be needed to neutralise the sodium hydroxide in the following titration. Some candidates approached the answer from a different direction...
— Examiner report, May/June 2023, 5070/41 Q2(g) (Cambridge)
Approximately half of the candidates recognised that the brown colour of the vinegar would mask the colour change of the indicator, making the colour change harder to see.
— Examiner report, May/June 2023, 5070/41 Q2(h) (Cambridge)
This longer question required candidates to carefully read the description given and respond appropriately. It was not expected that candidates were familiar with this specific experiment but tested their ability to apply their knowledge of laboratory skills and equipment. A number of candidates were able to answer this completely and obtain full credit. The best answers clearly referred to all th...
— Examiner report, May/June 2023, 5070/41 Q4 (Cambridge)
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