Acids, alkalis and titrations: Edexcel International GCSE Chemistry questions

Every Edexcel International GCSE Chemistry exam question on Acids, alkalis and titrations (specification points 2.28–2.33), 2019–2025, with its mark scheme and examiner’s report.

All 107 questions on Acids, alkalis and titrations, as a list

June 2025, Paper 2, Q5(a)(i) (1 mark): Name the most suitable piece of apparatus for measuring 25.0 cm3 of potassium hydroxide solution. (1)
June 2025, Paper 2, Q5(a)(ii) (1 mark): State why the student places the conical flask on a white tile. (1)
June 2025, Paper 2, Q5(b) (2 marks): The diagram shows the final burette reading. 32 33 The initial burette reading is given in the table. Complete the table, giving both values to the nearest 0.05
June 2025, Paper 2, Q5(c)(i) (1 mark): Place ticks (ü) in the table to show which results are concordant. (1)
June 2025, Paper 2, Q5(c)(ii) (1 mark): Use the concordant results to calculate the mean volume of sulfuric acid added. (1) mean volume of sulfuric acid = cm3.
June 2025, Paper 2, Q5(d)(i) (3 marks): The student uses 25.0 cm3 of potassium hydroxide solution with a concentration of 0.500 mol/dm3. The mean volume of sulfuric acid added is 26.50 cm3. This is th
June 2025 (R), Paper 2, Q6(a) (4 marks): Explain two improvements to the student’s method that would give more accurate results. (4) 1 2
June 2025 (R), Paper 2, Q6(b) (4 marks): The student repeats the titration correctly. The potassium hydroxide solution has a concentration of 0.150 mol / dm3 . The phosphoric acid solution has a concen
November 2024, Paper 2, Q5(a)(i) (1 mark): Give the name of the apparatus that the student should use to measure the volume of sodium hydroxide solution in step 1. (1)
November 2024, Paper 2, Q5(a)(ii) (1 mark): Give the colour change seen in step 4. (1)
November 2024, Paper 2, Q5(a)(iii) (1 mark): Give a reason why the student does not use universal indicator in this titration. (1)
November 2024, Paper 2, Q5(b)(i) (2 marks): Complete the table by adding the results from the rough titration. Record the volumes to the nearest 0.05 cm3 (2)
November 2024, Paper 2, Q5(b)(ii) (3 marks): Concordant results are results within 0.20 cm3 of each other. Use the concordant results from the table to calculate the mean volume of acid added. (3) mean vol
November 2024, Paper 2, Q7(b)(i) (4 marks): This is the equation for the reaction between dicarboxylic acid C and sodium hydroxide solution. HOOCCH2CH2COOH + 2NaOH → NaOOCH2CH2COONa + 2H2O 25.0 cm3 of 0.1
June 2024, Paper 2, Q7(b) (4 marks): When hydrogen chloride gas is dissolved in an organic solvent, the hydrogen chloride remains a covalent molecule. When hydrogen chloride gas is dissolved in wat
June 2024 (R), Paper 2, Q5(a)(i) (1 mark): Name a piece of apparatus that should be used to add 25.0 cm3 of sodium hydroxide solution to the conical flask. (1)
June 2024 (R), Paper 2, Q5(a)(ii) (5 marks): Describe the method the student should use to find the accurate volume of sodium hydrogensulfate solution needed to neutralise the 25.0 cm3 of sodium hydroxide
November 2023, Paper 1, Q7(c)(i) (1 mark): Give the colour of litmus in this solution. (1)
November 2023, Paper 1, Q7(c)(ii) (1 mark): Give the formula of the ion that causes the solution to be acidic. (1)
November 2023, Paper 2, Q6(a) (2 marks): The diagram shows two pieces of apparatus used in a titration. cm3 0 25 Not to scale cm3 50 X Y Give the names of these pieces of apparatus. (2) X Y
November 2023, Paper 2, Q6(b) (1 mark): Give the name of a suitable indicator that can be used in an acid-alkali titration. (1)
November 2023, Paper 2, Q6(c)(i) (3 marks): Calculate the volume of dilute nitric acid that the student would need to neutralise the sodium carbonate solution. (3) volume of nitric acid = cm3
June 2023, Paper 2, Q4(a) (1 mark): Give the name of the most suitable piece of apparatus to measure out 25.0 cm3 of potassium hydroxide solution. (1)
June 2023, Paper 2, Q4(b) (2 marks): Give the colour of methyl orange in potassium hydroxide solution and in dilute sulfuric acid. (2) colour in potassium hydroxide solution colour in dilute sulfur
June 2023, Paper 2, Q4(c) (1 mark): State why the student places the conical flask on a white tile. (1)
June 2023, Paper 2, Q4(d) (1 mark): State why the student swirls the flask continuously. (1)
June 2023, Paper 2, Q4(e) (1 mark): State what is meant by the term concordant results. (1)
June 2023, Paper 2, Q4(f) (3 marks): The student finds that 15.00 cm3 of sulfuric acid of concentration 0.180 mol / dm3 neutralises 25.0 cm3 of potassium hydroxide solution. This is the equation fo
June 2023, Paper 2, Q4(g) (2 marks): This is the ionic equation for the reaction between an acid and an alkali. H+(aq) + OH−(aq) → H2O(l) Explain why the OH− ion is a proton acceptor in this reacti
June 2023 (R), Paper 2, Q6(e) (3 marks): This is the equation for the reaction between sodium hydroxide and sulfuric acid. 2NaOH + H2SO4 → Na2SO4 + 2H2O A volume of 25.0 cm3 of sodium hydroxide solutio
January 2023, Paper 2, Q6(c)(ii) (6 marks): A student does a titration to find the accurate volume of sodium hydroxide solution needed for complete neutralisation. The student starts by using a pipette to
January 2023 (R), Paper 2, Q1(a) (1 mark): Give the pH value of a neutral solution. (1)
January 2023 (R), Paper 2, Q1(b) (1 mark): Give a pH value of a weakly acidic solution. (1)
January 2023 (R), Paper 2, Q7(a) (1 mark): Give the reason for using the white tile. (1)
January 2023 (R), Paper 2, Q7(b) (2 marks): Universal indicator is not a suitable indicator to use in a titration. Complete the table to show the name of a suitable indicator and its final colour in this
January 2023 (R), Paper 2, Q7(c) (5 marks): The student wants to obtain an accurate value for the volume of sodium hydroxide solution needed to neutralise the 25.0 cm3 of nitric acid. Describe all the fur
January 2023 (R), Paper 2, Q7(d)(i) (1 mark): Calculate the amount, in moles, of NaOH that reacts. (1) amount of NaOH = mol
January 2023 (R), Paper 2, Q7(d)(ii) (1 mark): Determine the amount, in moles, of HNO3 that reacts. (1) amount of HNO3 = mol
January 2023 (R), Paper 2, Q7(d)(iii) (1 mark): Calculate the concentration, in mol/dm3, of the HNO3 (1) concentration = mol/dm3
June 2022, Paper 2, Q2(a)(i) (2 marks): Give the name of each piece of apparatus. (2) X Y
June 2022, Paper 2, Q2(a)(ii) (1 mark): In a titration, a student adds 25.0 cm3 of barium hydroxide solution to a conical flask. Give a reason why it is better to use Y rather than X. (1)
June 2022, Paper 2, Q2(b)(i) (1 mark): State the colour of methyl orange in barium hydroxide solution. (1)
June 2022, Paper 2, Q2(b)(ii) (1 mark): Give a reason why universal indicator is not suitable for use in a titration. (1)
June 2022, Paper 2, Q2(c) (3 marks): The student adds some dilute nitric acid to a burette and does the titration. The equation for the reaction is Ba(OH)2 + 2HNO3 → Ba(NO3)2 + 2H2O The student fin
June 2022 (R), Paper 1, Q10(a)(i) (1 mark): Name a piece of apparatus the student could use to add 10.0 cm3 of dilute sulfuric acid to the beaker. (1)
June 2022 (R), Paper 2, Q6(a) (1 mark): State what is meant by concordant results. (1)
June 2022 (R), Paper 2, Q6(b) (4 marks): Explain two improvements to the student’s method so that more accurate results are obtained. (4)
June 2022 (R), Paper 2, Q6(c) (3 marks): The student makes the improvements and repeats the titration. The sulfuric acid has a concentration of 0.600 mol/dm3. The sodium hydroxide solution has a concen
January 2022, Paper 2, Q7(d) (3 marks): The ethanoic acid produced in the reaction is completely neutralised by 22.75 cm3 of 0.150 mol/dm3 barium hydroxide solution. The equation for the neutralisatio
January 2022 (R), Paper 1, Q1(a) (1 mark): Which of these is the colour of litmus indicator in an acidic solution? (1) A blue B orange C red D yellow
January 2022 (R), Paper 1, Q1(b) (1 mark): Which of these is the pH value of a neutral solution? (1) A 0 B 4 C 7 D 14
January 2022 (R), Paper 1, Q1(c) (1 mark): Which of these describes a solution with a pH value of 9? (1) A strongly acidic B strongly alkaline C weakly acidic D weakly alkaline
January 2022 (R), Paper 1, Q1(d) (1 mark): Which of these is the chemical formula of an acid? (1) A HNO3 B H2O C NaCl D NaOH
January 2022 (R), Paper 1, Q1(e) (1 mark): Name the type of reaction that occurs when an acid reacts with an alkali. (1)
January 2022 (R), Paper 2, Q3(a) (6 marks): The student wants to find the volume of sulfuric acid needed to neutralise 25.0 cm3 of the potassium hydroxide solution. Describe how the student should do this
January 2022 (R), Paper 2, Q3(b)(i) (2 marks): Calculate the amount, in moles, of KOH in 25.0 cm3 of potassium hydroxide solution of concentration 0.240 mol / dm3. (2) amount of KOH = mol
January 2022 (R), Paper 2, Q3(b)(ii) (1 mark): Calculate the amount, in moles, of H2SO4 in 15.00 cm3 of the sulfuric acid. (1) amount of H2SO4 = mol
January 2022 (R), Paper 2, Q3(b)(iii) (2 marks): Calculate the concentration, in mol / dm3, of the sulfuric acid. (2) concentration of sulfuric acid = mol / dm3
November 2021, Paper 2, Q4(c)(i) (1 mark): Identify the ion responsible for the colour change. (1)
November 2021, Paper 2, Q6(c)(i) (2 marks): The concentration of CH3COOH in vinegar can be found by titration with aqueous potassium hydroxide (KOH). The equation for the reaction is CH3COOH + KOH → CH3CO
June 2021, Paper 1, Q8(b)(i) (1 mark): Name the type of reaction that occurs between ammonia and sulfuric acid. (1)
June 2021, Paper 2, Q7(a) (3 marks): Give the names of X, Y and Z. (3) X Y Z
June 2021, Paper 2, Q7(b) (1 mark): What is the colour of phenolphthalein in phosphoric acid? (1) A blue B colourless C pink D red
June 2021, Paper 2, Q7(c)(i) (1 mark): Add ticks () to table 1 to show the concordant results. (1)
June 2021, Paper 2, Q7(c)(ii) (2 marks): Use your ticked results to calculate the mean (average) volume of NaOH added. (2) mean volume = cm3
June 2021, Paper 2, Q7(d)(i) (2 marks): Calculate the amount, in moles, of NaOH in 30.40 cm3 of sodium hydroxide solution. (2) amount = mol
June 2021, Paper 2, Q7(d)(ii) (1 mark): Calculate the amount, in moles, of H3PO4 in 25.0 cm3 of phosphoric acid. (1) amount = mol
June 2021, Paper 2, Q7(d)(iii) (2 marks): Calculate the concentration, in mol/dm3, of the phosphoric acid. (2) concentration = mol/dm3
January 2021 (R), Paper 2, Q6(a)(i) (1 mark): Name the piece of apparatus the student should use to add the potassium hydroxide solution. (1)
January 2021 (R), Paper 2, Q6(a)(ii) (1 mark): What is the colour of methyl orange in an alkaline solution? . (1) A blue B orange C red D yellow
January 2021 (R), Paper 2, Q6(b)(i) (1 mark): Place ticks () in the table to show which results are concordant. (1)
January 2021 (R), Paper 2, Q6(b)(ii) (2 marks): Use the concordant results to calculate the mean (average) volume of acid added. (2) mean volume = cm3
January 2021 (R), Paper 2, Q6(c)(i) (2 marks): Calculate the amount, in moles, of KOH in 25.0 cm3 of the potassium hydroxide solution. (2) amount of KOH = mol
January 2021 (R), Paper 2, Q6(c)(ii) (1 mark): Calculate the amount, in moles, of H2SO4 in 21.20 cm3 of sulfuric acid. (1) amount of H2SO4 = mol
January 2021 (R), Paper 2, Q6(c)(iii) (2 marks): Calculate the concentration, in mol/dm3, of the sulfuric acid. (2) concentration of sulfuric acid = mol/dm3
November 2020, Paper 1, Q4(a)(i) (1 mark): Identify the ion that makes the sodium hydroxide solution alkaline. (1)
November 2020, Paper 1, Q4(a)(ii) (1 mark): What is a possible pH of ammonia solution? (1) A 3 B 6 C 11 D 14
November 2020, Paper 1, Q4(b)(i) (1 mark): How does the sulfuric acid act in this reaction? (1) A as a neutron donor B as a neutron acceptor C as a proton donor D as a proton acceptor
November 2020, Paper 1, Q4(b)(ii) (1 mark): The diagram shows a beaker containing some ammonia solution and a few drops of phenolphthalein indicator. ammonia solution and phenolphthalein indicator Dilute
November 2020, Paper 2, Q6(c)(i) (1 mark): Name the piece of apparatus the student should use to measure 25.0 cm3 of the potassium hydroxide solution. (1)
November 2020, Paper 2, Q6(c)(ii) (2 marks): The concentration of potassium hydroxide in the solution is 0.125 mol/dm3. Calculate the amount, in mol, of KOH in 25.0 cm3 of this solution. (2) amount = mol
November 2020, Paper 2, Q6(c)(iii) (3 marks): The equation for the reaction in the titration is H2SO4 + 2KOH → K2SO4 + 2H2O Calculate the volume, in cm3, of 0.10 mol/dm3 sulfuric acid needed to neutralise 2
November 2020 (R), Paper 1, Q9(a)(i) (1 mark): Which of these could be the pH of this weak acid? (1) A 1 B 5 C 7 D 9
November 2020 (R), Paper 1, Q9(a)(ii) (1 mark): Which of these is a correct statement about acids? (1) A acids contain OH− ions B acids are electron donors C acids are proton acceptors D acids are proton dono
November 2020 (R), Paper 1, Q10(a)(i) (1 mark): Give a word equation for the reaction between potassium hydroxide and hydrochloric acid. (1)
November 2020 (R), Paper 2, Q6(b)(i) (2 marks): Give the colour of the phenolphthalein indicator in sodium hydroxide solution and in hydrochloric acid. (2) colour in sodium hydroxide solution colour in hydroc
November 2020 (R), Paper 2, Q6(b)(ii) (1 mark): Suggest why universal indicator is never used in a titration. (1)
November 2020 (R), Paper 2, Q6(d) (3 marks): The student needs 21.50 cm3 of hydrochloric acid to neutralise 25.0 cm3 of sodium hydroxide solution of concentration 0.800 mol/dm3. The equation for the reacti
January 2020, Paper 2, Q4(a) (2 marks): Give the colour change of the methyl orange indicator at the end‑point. (2) from to
January 2020, Paper 2, Q4(b) (4 marks): Describe four changes that the student could make to improve his plan. (4) 1 2 3 4
January 2020, Paper 2, Q4(c) (3 marks): The student then does the titration correctly. He finds that 16.70 cm3 of the dilute sulfuric acid neutralises 25.0 cm3 of sodium hydroxide solution of concentr
January 2020 (R), Paper 1, Q7(a)(i) (1 mark): State the piece of apparatus that should be used to measure 50 cm3 of hydrochloric acid. (1)
January 2020 (R), Paper 1, Q7(a)(ii) (1 mark): Name the type of reaction that occurs between hydrochloric acid and sodium hydroxide. (1)
January 2020 (R), Paper 1, Q7(b)(i) (1 mark): Determine the pH after 40 cm3 of sodium hydroxide solution has been added. (1)
January 2020 (R), Paper 1, Q7(b)(ii) (2 marks): Suggest the colour of the universal indicator paper when these volumes of sodium hydroxide solution have been added. (2) 15 cm3 30 cm3
January 2020 (R), Paper 1, Q7(b)(iii) (1 mark): Give the formula of the ion that causes sodium hydroxide to be alkaline. (1)
January 2020 (R), Paper 2, Q5(c)(ii) (3 marks): In a reaction between lithium and water, 150 cm3 of lithium hydroxide solution is formed. The lithium hydroxide solution is then completely neutralised by 24.85
June 2019 (R), Paper 2, Q6(a)(i) (1 mark): Name the piece of apparatus that would be most suitable for measuring the 25.0 cm3 of sodium hydroxide solution. (1)
June 2019 (R), Paper 2, Q6(a)(ii) (1 mark): Suggest why red wine would not be suitable to use for this investigation. (1)
June 2019 (R), Paper 2, Q6(a)(iii) (1 mark): State why she swirls the flask continuously. (1)
June 2019 (R), Paper 2, Q6(a)(iv) (1 mark): State why she adds the wine drop by drop near the end point. (1)
June 2019 (R), Paper 2, Q6(b) (3 marks): The diagram shows the burette readings at the start and end of one of the titrations. 1 22 2 23 3 24 start end Use the readings to complete the table. Give your
June 2019 (R), Paper 2, Q6(c)(i) (1 mark): Add ticks () to the table to show the concordant results. (1)
June 2019 (R), Paper 2, Q6(c)(ii) (2 marks): Use your ticked results to calculate the mean (average) volume of wine added. (2) mean volume of wine added = cm3
June 2019 (R), Paper 2, Q6(d)(i) (2 marks): The concentration of the sodium hydroxide solution is 0.0500 mol/dm3. Calculate the amount, in moles, of NaOH in 25.0 cm3 of sodium hydroxide solution. (2) amou
June 2019 (R), Paper 2, Q6(d)(ii) (1 mark): Deduce the amount, in moles, of CH3COOH in 19.50 cm3 of the wine. (1) amount of CH3COOH = mol
June 2019 (R), Paper 2, Q6(d)(iii) (2 marks): Calculate the concentration, in mol/dm3, of CH3COOH in the wine. (2) concentration of CH3COOH = mol/dm3

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