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Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter

Electrolysis

198 practice questions

Start practising (33 questions)

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Practice questions

31–33 of 33 · Hard

  1. Question 31

    7 marks · Hard

    A science teacher asks students to compare what happens at the cathode during the electrolysis of sodium chloride solution and copper(II) sulfate solution, both using inert electrodes.

    (a)

    Explain why the solution around the cathode becomes alkaline during the electrolysis of sodium chloride solution.

    [3 marks]
    (b)

    Explain why copper is deposited at the cathode instead of hydrogen during the electrolysis of copper(II) sulfate solution using inert electrodes.

    [2 marks]
    (c)

    In both electrolysis experiments above, water is present in solution. State one difference in the effect of prolonged electrolysis on the composition of the solution in each case, and explain your answer using the relevant ions.

    [2 marks]
    Answer and see the solution →

  2. Question 32

    7 marks · Hard

    A student investigates the products formed at the cathode when electrolysing sodium chloride solution and copper(II) sulfate solution, each with inert electrodes.

    (a)

    State the product formed at the cathode during the electrolysis of sodium chloride solution using inert electrodes.

    [1 mark]
    (b)

    Explain why hydrogen, not sodium, is produced at the cathode during the electrolysis of sodium chloride solution.

    [2 marks]
    (c)

    State the product formed at the cathode during the electrolysis of copper(II) sulfate solution using inert electrodes.

    [1 mark]
    (d)

    Explain why copper is deposited at the cathode during the electrolysis of copper(II) sulfate solution with inert electrodes.

    [2 marks]
    (e)

    In both experiments, describe one observation that could be made at the cathode, and explain how it relates to the product formed.

    [1 mark]
    Answer and see the solution →

  3. Question 33

    7 marks · Hard

    Electrolysis of sodium chloride solution and copper(II) sulfate solution can be represented by balanced half-equations.

    (a)

    Write a balanced half-equation for the reaction at the cathode during electrolysis of sodium chloride solution.

    [2 marks]
    (b)

    Write a balanced half-equation for the reaction at the anode during electrolysis of sodium chloride solution.

    [1 mark]
    (c)

    Write a balanced half-equation for the reaction at the cathode during electrolysis of copper(II) sulfate solution using inert electrodes.

    [2 marks]
    (d)

    Write a balanced half-equation for the reaction at the anode during electrolysis of copper(II) sulfate solution using inert electrodes.

    [2 marks]
    Answer and see the solution →