Identification of ions and gases: past paper questions

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• Question 40May/June 2026, paper 11Multiple choice1 mark

  J is an aqueous solution. When aqueous sodium hydroxide is added to J, a green precipitate is formed. The resulting mixture is heated, and no gas is formed.

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• Question 40Oct/Nov 2024, paper 11Multiple choice1 markHas a diagram

  An aqueous solution contains cations of metal X.

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• Question 40May/June 2026, paper 12Multiple choice1 mark

  An unknown salt, X, contains only one cation and only one anion. Aqueous sodium hydroxide is added to an aqueous solution of X.

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• Question 39Oct/Nov 2025, paper 12Multiple choice1 mark

  Solid J contains cations and chloride ions. The aqueous solution of J is colourless. Two separate samples of the solution are tested.

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• Question 40Oct/Nov 2024, paper 12Multiple choice1 mark

  Compound Q is soluble in water.

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• Question 40Oct/Nov 2023, paper 11Multiple choice1 markHas a diagram

  A student does two experiments. In experiment 1, ammonium carbonate is reacted with dilute hydrochloric acid. In experiment 2, ammonium carbonate is heated with aqueous sodium hydroxide.

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• Question 5May/June 2026, paper 21Structured14 marks

  Aluminium sulfate is prepared by reacting excess aluminium with hot dilute sulfuric acid.

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• Question 40Oct/Nov 2025, paper 12Multiple choice1 mark

  Solid Q reacts with dilute hydrochloric acid, producing a gas that turns limewater milky. Warming solid Q with aqueous sodium hydroxide produces a gas that turns damp red litmus paper blue. What is solid Q?

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• Question 1Oct/Nov 2024, paper 21Structured7 marksHas a diagram

  Fig. 1.1 shows the electronic configurations of five atoms, D, E, F, G and H. Answer the questions about these electronic configurations. Each electronic configuration may be used once, more than once or not at all.

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• Question 40Oct/Nov 2023, paper 12Multiple choice1 markHas a diagram

  The results of some tests on polluted river water are shown.

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• Question 5May/June 2026, paper 22Structured14 marks

  Zinc chloride is prepared by reacting excess zinc with warm dilute hydrochloric acid.

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• Question 3Oct/Nov 2025, paper 21Structured7 marksHas a diagram

  Sodium hydrogencarbonate decomposes when heated.

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• Question 5Oct/Nov 2024, paper 21Structured14 marksHas a diagram

  A student adds large pieces of copper(II) carbonate to dilute hydrochloric acid. The copper(II) carbonate is in excess. Complete the equation by adding state symbols for the products.

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• Question 1Oct/Nov 2023, paper 21Structured5 marks

  Choose from the list of compounds to answer these questions. calcium oxide carbon dioxide carbon monoxide lead chloride propan-1-ol sodium nitrate sodium sulfate sulfur dioxide water Each compound may be used once, more than once or not at all.

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• Question 3May/June 2026, paper 41Structured14 marks

  A student investigates aqueous solution, W, and a green solid, Y. W contains an unsaturated carboxylic acid. The student puts some W into a test-tube and adds aqueous bromine. Describe the observations the student makes.

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• Question 9Oct/Nov 2025, paper 21Structured10 marks

  Anhydrous copper(II) sulfate is a white solid. State the meaning of the term anhydrous.

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• Question 3Oct/Nov 2024, paper 41Structured14 marks

  A student investigates solid Y and solution Z. Solid Y is a white powder. The tests the student does on Y are shown in Table 3.1. Some of the observations for these tests are also shown.

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• Question 4Oct/Nov 2023, paper 21Structured10 marksHas a diagram

  Concentrated aqueous calcium bromide is electrolysed using graphite electrodes. Predict the product at each electrode.

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• Question 3May/June 2026, paper 42Structured14 marksHas a diagram

  A student investigates a pink solid, C, which contains two cations and one anion. (a) The student: • puts some C into a boiling tube • clamps the boiling tube as shown in Figure 3.1 • heats C • observes any changes that take place.

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• Question 3Oct/Nov 2025, paper 22Structured7 marksHas a diagram

  The equation for the reaction between aluminium and dilute hydrochloric acid is shown. $$2\mathrm{A}\mathrm{l}(\mathrm{s})+6\mathrm{H}\mathrm{C}\mathrm{l}(\mathrm{a}\mathrm{q})\to 2{\mathrm{A}\mathrm{l}\mathrm{C}\mathrm{l}}_3(\mathrm{a}\mathrm{q})+3{\mathrm{H}}_2(\mathrm{g})$$ Fig. 3.1 shows the reaction pathway diagram for this reaction.

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• Question 3Oct/Nov 2024, paper 42Structured14 marks

  A student investigates solution P and solution Q. Solution P is colourless and contains sodium ions. Describe how to do a flame test on solution P to confirm the identity of this cation.

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• Question 1Oct/Nov 2023, paper 22Structured5 marks

  Choose from the list of compounds to answer these questions. ammonia ethanol glucose magnesium chloride magnesium oxide methane nitrogen dioxide phosphorus(V) chloride poly(ethene) sodium bromide water Each compound may be used once, more than once or not at all.

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• Question 9Oct/Nov 2025, paper 22Structured9 marks

  Hydrated zinc chloride is a white solid. State the meaning of the term hydrated.

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• Question 4Oct/Nov 2023, paper 22Structured10 marksHas a diagram

  Concentrated aqueous magnesium iodide is electrolysed using graphite electrodes. Predict the product at each electrode.

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• Question 10Oct/Nov 2025, paper 22Structured7 marks

  Water is an important part of the environment. Rivers and lakes are natural sources of water. Name one substance in river water that may be harmful.

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• Question 30May/June 2024, paper 12Multiple choice1 mark

  The presence of water can be confirmed by the use of either anhydrous cobalt(II) chloride or anhydrous copper(II) sulfate. Which observation is correct if water is present?

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• Question 3Oct/Nov 2023, paper 41Structured14 marks

  A student investigates solution $\mathbf{X}$ and solution $\mathbf{Y}$. Both solutions are colourless. Part of the method for test 1 is missing.

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• Question 3Oct/Nov 2025, paper 41Structured14 marks

  A student does a series of tests using aqueous solution $\mathbf{Q}$ and aqueous solution $\mathbf{R}$. Solution $\mathbf{Q}$ is acidic. Solution $\mathbf{Q}$ contains one cation and one anion.

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• Question 3May/June 2024, paper 41Structured14 marks

  A student does a series of experiments to investigate solution $\mathbf{\text{R}}$. The student leaves a wooden splint with one end dipped into $\mathbf{\text{R}}$ for ten minutes. The student then places the damp end of the wooden splint into a blue Bunsen burner flame.

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• Question 1Oct/Nov 2023, paper 42Structured6 marksHas a diagram

  A student investigates the electrolysis of concentrated aqueous sodium chloride. Fig. 1.1 shows the apparatus the student uses. Name apparatus X.

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