Chemical tests: Edexcel International GCSE Chemistry questions

Every Edexcel International GCSE Chemistry exam question on Chemical tests (specification points 2.44–2.50), 2019–2025, with its mark scheme and examiner’s report.

All 83 questions on Chemical tests, as a list

June 2025, Paper 1, Q2(d) (1 mark): Lithium ions can be identified using a flame test. What flame colour indicates the presence of lithium ions? (1) A lilac B orange C red D yellow
June 2025, Paper 1, Q6(d) (2 marks): Describe a test to show that a solution contains Fe3+ ions. (2) test result
June 2025, Paper 2, Q6(a)(i) (1 mark): Give the test for hydrogen. (1)
June 2025 (R), Paper 1, Q11(a) (5 marks): A teacher finds an unlabelled bottle containing a white solid. Describe tests to show that the white solid is sodium sulfate. (5)
June 2025 (R), Paper 2, Q1(b) (2 marks): Describe a test to show that a gas is carbon dioxide. (2)
June 2025 (R), Paper 2, Q3(c)(i) (1 mark): Describe a test to show that oxygen gas is produced. (1)
November 2024, Paper 1, Q2(a)(iii) (1 mark): Name the gas that can bleach damp litmus paper. (1)
November 2024, Paper 1, Q5(a) (1 mark): Give the test for oxygen gas. (1)
November 2024, Paper 1, Q7(b) (2 marks): Describe a chemical test the student can use to show that the liquid in tube B contains water. (2)
November 2024, Paper 2, Q2(c) (2 marks): A student has a solution of iron(II) sulfate and a solution of iron(III) sulfate. Describe a chemical test the student could use to identify which solution is i
June 2024, Paper 1, Q1(b) (2 marks): Describe a test for chlorine. (2)
June 2024, Paper 1, Q6(b)(i) (2 marks): Explain why the student needs to clean the platinum wire. (2)
June 2024, Paper 1, Q6(b)(ii) (1 mark): What is the colour of the flame if the solid contains lithium ions? (1) A lilac B orange C red D yellow
June 2024, Paper 1, Q7(d)(ii) (6 marks): A technician finds an unlabelled bottle on a shelf that could be ammonium carbonate solution. Describe tests that the technician should do to confirm that the s
June 2024 (R), Paper 1, Q4(b) (2 marks): Give a test to show that, at the end of the reaction, the solution contains sodium ions. (2)
June 2024 (R), Paper 2, Q6(a)(ii) (1 mark): Give a test to show that the gas produced at the positive electrode is oxygen. (1)
June 2024 (R), Paper 2, Q6(a)(iii) (1 mark): Give a test to show that the gas produced at the negative electrode is hydrogen. (1)
November 2023, Paper 1, Q6(a) (1 mark): Give the test for oxygen. (1)
November 2023, Paper 1, Q7(a) (6 marks): A technician needs to identify the solution in an unlabelled bottle. The technician knows that the solution contains one of these compounds. • iron(II) bromide
November 2023, Paper 2, Q6(d) (3 marks): Describe a test to show that sodium carbonate solution contains carbonate ions. (3)
November 2023, Paper 2, Q7(c)(i) (1 mark): Give a test for hydrogen. (1)
June 2023, Paper 1, Q2(b)(ii) (1 mark): Give a test for hydrogen. (1)
June 2023, Paper 1, Q5(b) (5 marks): An unlabelled bottle containing a white powder is found in a laboratory. Describe tests to show that the white powder in the bottle is lithium carbonate. (5)
June 2023, Paper 2, Q5(a) (2 marks): Describe how the student could test a sample of copper(II) sulfate solution to show that it contains copper(II) ions. (2)
June 2023, Paper 2, Q5(d)(i) (1 mark): Give a test for oxygen. (1)
June 2023 (R), Paper 1, Q9(b) (6 marks): A student has four unlabelled beakers, each containing a colourless solution of a different salt. These are the four salt solutions. • calcium bromide • calcium
June 2023 (R), Paper 2, Q6(b)(i) (1 mark): Give the test for hydrogen gas. (1)
January 2023, Paper 1, Q2(d)(iii) (2 marks): After one day the student does two tests on the liquid in the beaker. The table shows the student’s results. Test Result flame test lilac flame addition of acid
January 2023, Paper 1, Q12(c)(ii) (2 marks): Describe how the reaction can be used to show that a liquid contains water. (2)
January 2023 (R), Paper 1, Q6(a)(iii) (2 marks): Describe a test for chlorine gas. (2)
January 2023 (R), Paper 1, Q8(b)(i) (2 marks): Complete the diagram to show what needs to be added to the apparatus to test that the gas released is carbon dioxide. (2)
January 2023 (R), Paper 1, Q8(b)(ii) (1 mark): Give the result of the test. (1)
January 2023 (R), Paper 1, Q10(d) (3 marks): Describe a test to show that the ammonium nitrate solution contains ammonium ions. (3)
June 2022, Paper 1, Q6(a)(ii) (1 mark): Give the test for hydrogen. (1)
June 2022, Paper 1, Q10(b)(iii) (3 marks): Describe a test for ammonium ions. (3)
June 2022, Paper 2, Q1(c) (2 marks): Describe a test for carbon dioxide. (2)
June 2022, Paper 2, Q3(d)(ii) (5 marks): Describe tests to show that the product of the reaction is lithium chloride. (5)
June 2022 (R), Paper 1, Q2(b)(ii) (2 marks): Describe a chemical test to show that the sodium chloride solution contains chloride ions. (2)
June 2022 (R), Paper 2, Q4(b)(iii) (1 mark): Give a test for oxygen. (1)
January 2022, Paper 1, Q6(d) (2 marks): Give a test to show that sodium oxide contains sodium ions. (2)
January 2022, Paper 1, Q7(b)(i) (1 mark): State the colour of the precipitate of silver chloride. (1)
January 2022, Paper 1, Q11(a)(i) (2 marks): Describe a chemical test to show that the colourless liquid contains water. (2)
January 2022 (R), Paper 1, Q9(a) (2 marks): Give two reasons why the student should know, without doing any tests, that one of the compounds cannot be copper(II) carbonate. (2) 1 2
January 2022 (R), Paper 1, Q9(b) (6 marks): Describe tests the student could do to show that the mixture contains potassium carbonate and potassium iodide. (6)
November 2021, Paper 1, Q5(b)(ii) (1 mark): Give the change in the appearance of the limewater. (1)
November 2021, Paper 1, Q8(b) (2 marks): A colourless solution contains sodium carbonate and sodium sulfate. Describe a test using barium chloride to show that the colourless solution contains sulfate
November 2021, Paper 1, Q10(c)(i) (2 marks): Describe a chemical test to show that the colourless liquid contains water. (2)
June 2021, Paper 1, Q1(b) (2 marks): Describe a test for carbon dioxide. (2)
June 2021, Paper 1, Q6(b)(i) (2 marks): Explain why the student needs to clean the platinum wire. (2)
June 2021, Paper 1, Q6(b)(ii) (1 mark): Which of these is the colour of the flame if the solid contains sodium ions? (1) A green B lilac C red D yellow
June 2021, Paper 1, Q8(a) (6 marks): A scientist finds an unlabelled bottle on a shelf. She thinks the bottle contains a solution of ammonium sulfate, (NH4)2SO4 Describe tests the scientist could d
June 2021, Paper 2, Q6(a)(i) (1 mark): Give a test for hydrogen gas. (1)
June 2021, Paper 2, Q6(a)(ii) (2 marks): Give a test for chlorine gas. (2)
January 2021, Paper 1, Q6(b) (6 marks): A student has four unlabelled beakers, each containing a colourless solution of a different salt. The four solutions are • potassium carbonate • potassium chlor
January 2021, Paper 1, Q11(a)(i) (1 mark): Give the test for oxygen gas. (1)
January 2021, Paper 2, Q2(b) (1 mark): Describe the test for hydrogen gas. (1)
January 2021 (R), Paper 1, Q6(a)(ii) (1 mark): Give a test for hydrogen gas. (1)
January 2021 (R), Paper 1, Q10(c)(ii) (2 marks): Describe a test for calcium ions in the sample of gypsum. (2)
January 2021 (R), Paper 2, Q8(a)(i) (1 mark): Give a chemical equation for this reaction. (1)
January 2021 (R), Paper 2, Q8(a)(ii) (2 marks): Give a test for ammonia gas. (2)
November 2020, Paper 2, Q6(a)(iii) (1 mark): Which of these tests shows that the gas formed at the cathode is hydrogen? (1) A a glowing splint relights B a burning splint gives a squeaky pop C a burning sp
November 2020, Paper 2, Q6(b) (2 marks): Describe a test to show that solution X contains sulfate ions. (2)
November 2020 (R), Paper 1, Q4(b) (1 mark): Give a test for oxygen. (1)
November 2020 (R), Paper 1, Q6(a)(iii) (2 marks): Give a test for chlorine gas. (2)
November 2020 (R), Paper 1, Q6(b) (3 marks): Give a test to show that a solution contains iodide ions. (3) test result
November 2020 (R), Paper 2, Q4(b)(ii) (2 marks): Give a test to show that lithium fluoride contains lithium ions. (2)
January 2020, Paper 1, Q7(c) (6 marks): A technician sees an unlabelled bottle containing a liquid. He knows that the liquid is a solution of one of these compounds. ● copper(II) chloride ● copper(II)
January 2020, Paper 1, Q8(a)(ii) (2 marks): Describe the test for carbon dioxide gas. (2)
January 2020, Paper 2, Q1(a) (1 mark): Name the element that burns with a lilac flame. (1)
January 2020, Paper 2, Q5(a) (1 mark): Which is a correct statement about oxygen? (1) A it burns with a squeaky pop B it relights a glowing splint C it turns blue litmus red D it turns limewater milk
January 2020 (R), Paper 1, Q4(b) (3 marks): Describe a test to show that ammonium chloride contains ammonium ions. (3)
January 2020 (R), Paper 1, Q8(b) (4 marks): Describe tests to show that an aqueous solution of calcium chloride contains calcium ions and chloride ions. (4) calcium ions chloride ions
January 2020 (R), Paper 2, Q3(c) (1 mark): Acidified silver nitrate solution is used to test for chloride ions. Give a reason why hydrochloric acid is not used to acidify silver nitrate solution. (1)
January 2020 (R), Paper 2, Q5(a)(ii) (1 mark): Give the test for hydrogen gas. (1)
June 2019, Paper 1, Q3(a) (1 mark): Give the formula of the ion that produces the red flame. (1)
June 2019, Paper 1, Q3(b) (1 mark): Name the cream precipitate. (1)
June 2019, Paper 1, Q3(c) (1 mark): Identify the white solid. (1)
June 2019, Paper 1, Q3(d)(i) (1 mark): State why the wire should be clean when used in the flame test. (1)
June 2019, Paper 1, Q3(d)(ii) (2 marks): The table lists properties of some metals. Add ticks () to the table to show the two properties needed in a metal wire used in a flame test. (2) Property good
June 2019, Paper 1, Q11(b)(ii) (2 marks): Describe how anhydrous copper(II) sulfate is used to test for water. (2) 16
June 2019, Paper 1, Q11(b)(iii) (3 marks): Explain the change in appearance of the limewater. (3)
June 2019, Paper 1, Q15(a) (3 marks): Complete the table to show the observation made in each test. (3)
June 2019 (R), Paper 2, Q1(b) (1 mark): Describe the test for oxygen. (1)

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