Tests for ions and instrumental analysis: Edexcel GCSE Chemistry questions

Every Edexcel GCSE Chemistry exam question on Tests for ions and instrumental analysis (specification points 9.1–9.9), 2018–2025, with its mark scheme and examiner’s report.

All 106 questions on Tests for ions and instrumental analysis, as a list

June 2025, Paper 1 Foundation, Q9(a)(i) (2 marks): Complete the equation for this reaction, including the missing state symbol. (2) AgNO3(aq) + KCl( ) → AgCl(s) + (aq)
June 2025, Paper 1 Foundation, Q9(a)(ii) (1 mark): Give the name of the white precipitate that forms. (1)
June 2025, Paper 1 Foundation, Q9(c)(i) (1 mark): What are the meanings of these two symbols? (1) A flammable and toxic B harmful and dangerous to the environment C toxic and dangerous to the environment D toxi
June 2025, Paper 1 Foundation, Q9(c)(ii) (1 mark): State a safety step that should be taken when using the unknown solution. (1)
June 2025, Paper 2 Higher, Q1(a) (1 mark): A student carries out a flame test on a salt. The student observes a yellow flame. Which ion is in the salt? (1) A Ca2+ B Cu2+ C Na+ D Li+
June 2025, Paper 2 Higher, Q9(a) (1 mark): Figure 12 shows the calibration graph of a flame photometer for the concentration of calcium ions in a solution. 300 photometer reading 250 200 150 100 50 0 0 0
June 2025, Paper 2 Higher, Q9(b)(i) (1 mark): Calculate the mean concentration of sodium ions in the three bottled waters. (1) mean concentration = mg dm–3
June 2025, Paper 2 Higher, Q9(b)(ii) (3 marks): Calculate the volume of tap water, in dm3, that contains 3 moles of sodium ions. (relative atomic mass: Na = 23) (3) volume = dm3
June 2025, Paper 2 Higher, Q9(c) (4 marks): A student is given two test tubes, one containing solid aluminium chloride and the other containing solid calcium chloride. Describe the test the student should
June 2025, Paper 2 Higher, Q9(d) (3 marks): Silver carbonate and silver bromide are both insoluble solids. A student tests a solution to see if it contains bromide ions. The student adds a few drops of si
June 2025, Paper 2 Foundation, Q2(a) (3 marks): Flame tests can be used to identify some metal ions. Draw one straight line from each flame colour to the metal ion that produces that flame colour. (3) flame c
June 2025, Paper 2 Foundation, Q2(b)(i) (2 marks): Write the word equation for this reaction. (2) →
June 2025, Paper 2 Foundation, Q2(b)(ii) (1 mark): Copper hydroxide contains copper ions, Cu2+. What colour is copper hydroxide? (1) A yellow B red-brown C green D blue
June 2024, Paper 2 Higher, Q4(a)(i) (2 marks): Explain a safety precaution that should be taken when using a substance with the hazard symbol shown in Figure 6. (2)
June 2024, Paper 2 Higher, Q4(a)(ii) (1 mark): Substance K has the formula AgNO3 . Give the name of substance K. (1)
June 2024, Paper 2 Higher, Q4(a)(iv) (2 marks): A student tests a solid for chloride ions. The student uses the following method. step 1 dissolve a small amount of the solid in water step 2 add some dilute hy
June 2024, Paper 2 Higher, Q4(b) (3 marks): In the test for carbonate ions, the carbonate ions react with an acid. Sodium carbonate, Na2CO3 , is reacted with dilute hydrochloric acid. Complete and balance
June 2024, Paper 2 Higher, Q8(a)(i) (2 marks): Explain why this conclusion may not be correct. (2)
June 2024, Paper 2 Higher, Q8(a)(ii) (2 marks): Describe a test the student could use to confirm that the solid contains sulfate ions. (2)
June 2024, Paper 2 Higher, Q8(b) (1 mark): A solution containing iron ions is mixed with sodium hydroxide solution. A green precipitate forms. After a period of time exposed to air, the precipitate chang
June 2024, Paper 2 Higher, Q8(c) (6 marks): A technician has samples of two substances, R and S. R is an ionic solid. Molecules of S contain 2 carbon atoms. The technician carries out some tests on R and
June 2024, Paper 2 Foundation, Q3(a) (1 mark): The precipitates formed in this test are solids. Which state symbol is used for precipitates in equations? (1) A aq B g C l D s
June 2024, Paper 2 Foundation, Q3(b) (3 marks): A student is given a container of solid A and a bottle of dilute sodium hydroxide solution. Describe how the student should carry out the test in Figure 5. Incl
June 2024, Paper 2 Foundation, Q3(c)(i) (1 mark): State what would be seen when iron(II) chloride is tested. (1)
June 2024, Paper 2 Foundation, Q3(c)(ii) (1 mark): What is the formula of an iron(II) ion? (1) A Fe2 B Fe2 + C 2Fe+ D Fe2+
June 2024, Paper 2 Foundation, Q3(d)(i) (1 mark): When the sodium hydroxide solution is added, no precipitate forms. State what can be concluded from this result. (1)
June 2024, Paper 2 Foundation, Q3(d)(ii) (2 marks): In an experiment, the height of the precipitate formed in a reaction is measured using a 10 cm ruler. The apparatus is shown in Figure 6. cm test tube ruler pre
June 2024, Paper 2 Foundation, Q10(a)(i) (2 marks): Explain a safety precaution that should be taken when using a substance with the hazard symbol shown in Figure 17. (2)
June 2024, Paper 2 Foundation, Q10(a)(ii) (1 mark): Substance K has the formula AgNO3 . Give the name of substance K. (1)
June 2024, Paper 2 Foundation, Q10(a)(iv) (2 marks): A student tests a solid for chloride ions. The student uses the following method. step 1 dissolve a small amount of the solid in water step 2 add some dilute hy
June 2024, Paper 2 Foundation, Q10(b) (3 marks): In the test for carbonate ions, the carbonate ions react with an acid. Sodium carbonate, Na2CO3 , is reacted with dilute hydrochloric acid. Complete and balance
June 2023, Paper 2 Higher, Q10(a)(i) (2 marks): The student made the following observation and conclusion. ‘I saw that the flame colour was yellow so the sample must contain sodium ions.’ Due to the way the s
June 2023, Paper 2 Higher, Q10(a)(ii) (1 mark): What colour should the student have seen in the flame if the test had been carried out correctly? (1) A blue-green B lilac C orange-red D red
June 2023, Paper 2 Higher, Q10(b) (3 marks): A sample of the potassium chloride was also tested for chloride ions. Describe the test for chloride ions. (3)
June 2023, Paper 2 Higher, Q10(c)(ii) (3 marks): When the barium chloride solution was added to the aluminium sulfate solution, a precipitate was formed. The balanced equation for this reaction is 3BaCl2(aq) +
June 2023, Paper 2 Foundation, Q3(a)(i) (2 marks): Complete step 2 of how to carry out a flame test. (2) step 1 dip a flame test wire in dilute hydrochloric acid and then hold the wire in a roaring Bunsen flame
June 2023, Paper 2 Foundation, Q3(a)(ii) (3 marks): Many metal ions produce a coloured flame in a flame test. Draw one straight line from each metal ion to its flame colour in a flame test. (3) metal ion flame co
June 2023, Paper 2 Foundation, Q3(b) (1 mark): Some metal ions can be identified using sodium hydroxide solution. Drops of sodium hydroxide solution were added to a solution containing iron(III) ions, Fe3+.
June 2023, Paper 2 Foundation, Q3(c)(i) (1 mark): Give the name of this gas. (1)
June 2023, Paper 2 Foundation, Q3(c)(ii) (1 mark): Figure 6 shows the apparatus that a student set up to test for this gas. limewater Figure 6 This apparatus will not work. State what change is needed so that bu
June 2023, Paper 2 Foundation, Q3(d) (1 mark): A compound that contained ammonium ions was dissolved in water. A solution was formed. Sodium hydroxide solution was added, and the mixture was heated. A gas wa
June 2022, Paper 2 Higher, Q4(a)(i) (2 marks): The acid in Figure 6 can be used in the test for carbonate ions. Explain, giving the name of the hazard symbol shown, what safety precautions should be taken wh
June 2022, Paper 2 Higher, Q4(b)(i) (2 marks): This method did not work well. Explain an improvement that needs to be made to step 3 to enable a bright flame colour to be produced. (2)
June 2022, Paper 2 Higher, Q4(b)(ii) (3 marks): Figure 7 shows the results of the flame tests on three compounds, P, Q and R. compound flame colour P red Q lilac R blue‑green Figure 7 Use Figure 7 to identify
June 2022, Paper 2 Higher, Q4(c) (2 marks): A flame photometer was used to analyse samples of a solution of metal ions. Each sample was treated with 5.00 cm3 of dilute hydrochloric acid. 1.00 dm3 of the a
June 2022, Paper 2 Higher, Q8(a)(i) (1 mark): Which of these is evidence of a precipitate being produced? (1) A fizzing B solid forms in the solution C the solution turns purple D the solution gets hot
June 2022, Paper 2 Higher, Q8(a)(ii) (4 marks): You are given two solutions, one containing Ca2+ ions and the other containing Al3+ ions. Devise a plan to identify which solution is which. (4)
June 2022, Paper 2 Higher, Q8(b) (6 marks): A scientist carries out some tests on solid V and on a solution of V. The tests and results are shown in Figure 11. test result appearance of V white solid see
June 2022, Paper 2 Foundation, Q3(a)(i) (2 marks): Describe how to make a solution from a solid in a test tube. (2)
June 2022, Paper 2 Foundation, Q3(a)(ii) (1 mark): Give the name of the apparatus that should be used to add a few drops of silver nitrate solution to the test tube. (1)
June 2022, Paper 2 Foundation, Q3(a)(iii) (1 mark): When an equation is written for this reaction, which state symbol is used for the silver nitrate solution? (1) A aq B g C l D s
June 2022, Paper 2 Foundation, Q3(b)(i) (1 mark): When one compound is tested, a precipitate is seen. State what you see when a precipitate forms. (1)
June 2022, Paper 2 Foundation, Q3(b)(ii) (1 mark): Using Figure 5, name the ion in the compound that causes a cream precipitate. (1) ion
June 2022, Paper 2 Foundation, Q3(c)(i) (1 mark): Using Figure 5, name the compound. (1)
June 2022, Paper 2 Foundation, Q10(a)(i) (2 marks): The acid in Figure 17 can be used in the test for carbonate ions. Explain, giving the name of the hazard symbol shown, what safety precautions should be taken w
June 2022, Paper 2 Foundation, Q10(b)(i) (2 marks): This method did not work well. Explain an improvement that needs to be made to step 3 to enable a bright flame colour to be produced. (2)
June 2022, Paper 2 Foundation, Q10(b)(ii) (3 marks): Figure 18 shows the results of the flame tests on three compounds, P, Q and R. compound flame colour P red Q lilac R blue‑green Figure 18 Use Figure 18 to ident
June 2022, Paper 2 Foundation, Q10(c) (2 marks): A flame photometer was used to analyse samples of a solution of metal ions. Each sample was treated with 5.00 cm3 of dilute hydrochloric acid. 1.00 dm3 of the a
November 2021, Paper 2 Higher, Q7(a)(i) (3 marks): The technician first produced a calibration curve using solutions with known concentrations of potassium ions. Figure 9 contains the data for the calibration cu
November 2021, Paper 2 Higher, Q7(a)(ii) (1 mark): The technician then obtained a reading of 360 for a dilute solution containing potassium ions. Use the calibration curve to find the concentration of the potass
November 2021, Paper 2 Higher, Q7(b) (2 marks): In the test for chloride ions, silver nitrate solution is added to a solution containing chloride ions. A white precipitate forms. Write the ionic equation for
November 2021, Paper 2 Higher, Q7(c) (6 marks): A student was given a container of ammonium iron(II) sulfate, (NH4)2Fe(SO4)2. The student was also given a dilute solution of sodium hydroxide and access to oth
November 2021, Paper 2 Foundation, Q4(a)(i) (1 mark): State why in step 1 the wire is dipped in hydrochloric acid and held in a roaring Bunsen burner flame. (1)
November 2021, Paper 2 Foundation, Q4(a)(ii) (1 mark): State why in step 2 the wire is dipped in hydrochloric acid again before dipping it in the copper sulfate crystals. (1)
November 2021, Paper 2 Foundation, Q4(a)(iii) (1 mark): What colour should be seen when the flame test is carried out on copper sulfate? (1) A blue-green B lilac C orange-red D yellow
November 2021, Paper 2 Foundation, Q4(b)(i) (1 mark): Give an advantage of using a flame photometer, rather than a flame test, to test for copper ions. (1)
November 2021, Paper 2 Foundation, Q4(b)(ii) (1 mark): Figure 7 shows some values obtained when producing a calibration graph for copper ions in a flame photometer. Draw a line of best fit through the points. (1) di
November 2021, Paper 2 Foundation, Q4(b)(iii) (1 mark): A solution containing copper ions gave a display reading of 0.030. Use the calibration graph in Figure 7 to find the concentration of copper ions in this soluti
November 2021, Paper 2 Foundation, Q4(c) (2 marks): The student tested an unknown solution for sulfate ions by 1. adding a few drops of dilute sulfuric acid to the unknown solution 2. then adding a few drops of b
November 2020, Paper 2 Higher, Q1(b)(i) (2 marks): The solution is tested to see whether it contains one of these ions. In the test, a few drops of two different solutions are added to X. Name the two solutions
November 2020, Paper 2 Higher, Q1(b)(ii) (2 marks): The student carrying out the test records the following result. A precipitate forms in the test tube. The precipitate is a cream/yellow colour. Explain why the
November 2020, Paper 2 Higher, Q1(b)(iii) (1 mark): The metal ions in X could be identified using a flame test. There is a more sensitive and accurate instrumental method that can be used. Give the name of an ins
November 2020, Paper 2 Higher, Q5(b) (2 marks): Some polymerisation reactions produce ammonia as a waste product. A student is given a sample of pure, dry ammonia gas. The student suggests the following metho
November 2020, Paper 2 Foundation, Q4(a)(i) (2 marks): Describe how to do a flame test. (2)
November 2020, Paper 2 Foundation, Q4(a)(ii) (2 marks): Different metal ions produce different coloured flames. Draw one straight line from each metal ion to its flame colour. (2) metal ion flame colour green calcium
November 2020, Paper 2 Foundation, Q4(b)(i) (2 marks): The anions in solutions of P and Q can be identified from the results of the tests shown in Figure 7. Draw one straight line from each solution to the anion pre
November 2020, Paper 2 Foundation, Q4(c)(i) (2 marks): State what would be seen. (2)
November 2020, Paper 2 Foundation, Q4(c)(ii) (1 mark): One other product is formed in this reaction. What is the name of this other product? (1) A iron(II) chloride B sodium chloride C sodium sulfate D water
June 2019, Paper 2 Higher, Q10(a) (2 marks): A sample of potassium carbonate is contaminated with a small amount of sodium carbonate. When a flame test is carried out on the sample, a bright yellow flame i
June 2019, Paper 2 Higher, Q10(b) (3 marks): Hydrochloric acid reacts with a solution of sodium carbonate. 2HCl(aq) + Na2CO3(aq) → 2NaCl(aq) + CO2(g) + H2O(l) (3) Write the ionic equation for this reaction
June 2019, Paper 2 Higher, Q10(c) (6 marks): A student tests solutions of three ionic substances, K, L and M. The student carries out the same two tests on each of the three solutions. Test 1 add dilute ni
June 2019, Paper 2 Foundation, Q7(a)(i) (2 marks): Explain why the test for a given ion must be unique to that ion. (2)
June 2019, Paper 2 Foundation, Q7(a)(ii) (1 mark): In the test for the carbonate ion, CO3 solid being tested. State the name of the gas produced in the test if carbonate ions are present. (1)
June 2019, Paper 2 Foundation, Q7(a)(iii) (3 marks): Tests for three ions are described. Draw one straight line from the test for each ion to the observation that shows that ion to be present. Each observation may
June 2019, Paper 2 Foundation, Q7(b) (6 marks): A white solid is known to be a chloride in which the metal ion is sodium, potassium, calcium or aluminium. A chemist was told to carry out a test for each metal
June 2018, Paper 2 Higher, Q8(a) (2 marks): Solid X contains two ions. The tests for these ions and their results are shown in Figure 10. test result flame test on solid X red-orange flame dilute nitric a
June 2018, Paper 2 Higher, Q8(b)(i) (1 mark): Give the reason why this test does not identify the cation in solid Y. (1)
June 2018, Paper 2 Higher, Q8(b)(ii) (1 mark): Give the reason why this test does not identify the anion in solid Y. (1)
June 2018, Paper 2 Higher, Q8(c) (1 mark): Instrumental methods are often used for analysis. Give a reason why instrumental analysis may be better than other methods of analysis. (1)
June 2018, Paper 2 Higher, Q8(d)(i) (3 marks): Write the ionic equation for this reaction. (3)
June 2018, Paper 2 Higher, Q8(d)(ii) (2 marks): The green iron(II) hydroxide precipitate gradually turns brown when exposed to air. Explain this observation. (2)
June 2018, Paper 2 Foundation, Q2(a) (1 mark): Which ion is shown to be present by the result of test 1? (1) A lithium B sodium C potassium D calcium
June 2018, Paper 2 Foundation, Q2(b)(i) (1 mark): State the name of the gas given off in test 2. (1)
June 2018, Paper 2 Foundation, Q2(b)(ii) (1 mark): State the name of the ion shown to be present in the white solid by the result of test 2. (1)
June 2018, Paper 2 Foundation, Q2(c)(i) (2 marks): A solution containing a concentration of potassium ions of 35 mg dm−3 is placed in the photometer. The photometer reading is 7.0. Plot this point on the graph a
June 2018, Paper 2 Foundation, Q2(c)(ii) (1 mark): Another solution of potassium ions gives a photometer reading of 9.0. Use the graph to find the concentration of potassium ions in this solution. (1) concentrat
Specimen, Paper 2 Higher, Q5(a) (2 marks): A student carries out a flame test on an unknown solid. A red flame is seen. The student concludes that the solid is lithium carbonate. Explain why this conclus
Specimen, Paper 2 Higher, Q5(b) (2 marks): The following tests were carried out on a substance containing two ions. 1. A flame test on the solid substance produced a yellow colour. 2. Dilute hydrochloric
Specimen, Paper 2 Higher, Q5(c) (1 mark): The test for chloride ions was carried out on a solution. Dilute nitric acid was added to the solution, followed by a few drops of silver nitrate solution. A wh
Specimen, Paper 2 Higher, Q5(d)(i) (2 marks): Sodium hydroxide solution is warmed with a solution of ammonium ions. Ammonia gas is given off. Describe the test to show the gas is ammonia. (2)
Specimen, Paper 2 Higher, Q5(d)(ii) (2 marks): Sodium hydroxide solution is also used to distinguish between iron(II) ions, Fe2+ and iron(III) ions, Fe3+, in solution. You are given a solution containing iro
Specimen, Paper 2 Higher, Q5(d)(iii) (1 mark): Iron(III) ions, Fe3+, react with hydroxide ions in solution to form iron(III) hydroxide. Complete the ionic equation for this reaction. (1) Fe3+ + 3OH– →
Specimen, Paper 2 Foundation, Q10(a) (2 marks): Sodium hydroxide solution is warmed with a solution of ammonium ions. Ammonia gas is given off. Describe the test to show the gas is ammonia. (2)
Specimen, Paper 2 Foundation, Q10(b)(i) (2 marks): Sodium hydroxide solution was added to a small amount of copper sulfate solution. A blue precipitate of copper hydroxide formed. Complete the word equation for
Specimen, Paper 2 Foundation, Q10(b)(ii) (1 mark): Dilute hydrochloric acid was added to a different sample of copper sulfate solution. Barium chloride solution was then added. State what would be seen. (1)
Specimen, Paper 2 Foundation, Q10(c) (6 marks): A technician found some colourless crystals in an unlabelled beaker in a laboratory. The technician knew that the substance was potassium chloride, potassium ca

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