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

Electrolysis

198 practice questions

Topics covered

Practice questions

81–90 of 198

  1. Question 81

    1 mark · Easy

    How many electrons are required to balance the following ionic half-equation for the reduction of potassium ions during the electrolysis of molten potassium chloride?

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  2. Question 82

    3 marks · Easy

    This question is about the electrolysis of molten lithium bromide.

    (a)

    Name the particle that moves towards the anode.

    [1 mark]
    (b)

    State the element formed at the cathode.

    [1 mark]
    (c)

    Explain, using ions, how you know which element forms at the cathode.

    [1 mark]
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  3. Question 83

    2 marks · Easy

    Write the balanced ionic half-equation for oxygen formation at the anode during the electrolysis of molten aluminium oxide.

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  4. Question 84

    2 marks · Normal

    Write the ionic half-equations for the electrolysis of molten magnesium chloride. Identify which half-equation is for the cathode and which is for the anode.

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  5. Question 85

    4 marks · Normal

    This question is about the electrolysis of molten lead(II) bromide.

    (a)

    Write the balanced ionic half-equation for the reaction at the cathode.

    [2 marks]
    (b)

    Write the balanced ionic half-equation for the reaction at the anode.

    [2 marks]
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  6. Question 86

    3 marks · Normal

    A chemist electrolyses molten potassium iodide (KI).

    Predict which element is formed at (a) the cathode and (b) the anode. Explain your reasoning in each case.

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  7. Question 87

    3 marks · Normal

    During the electrolysis of molten aluminium oxide, explain how you can check that each ionic half-equation is correctly balanced. Include checks for both the numbers of atoms and the charges.

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  8. Question 88

    4 marks · Normal

    Student equations for the electrolysis of molten calcium bromide
    StudentCathode equationAnode equation
    ACa^{2+} + 2e^- \to Ca2Br^- \to Br_2 + 2e^-
    BCa^{2+} \to Ca + 2e^-Br^- \to Br_2 + 2e^-
    CCa^{2+} + e^- \to Ca2Br^- \to Br_2 + 2e^-
    DCa^{2+} + 2e^- \to Ca2Br^- \to Br_2 + e^-

    Use the table above. For each equation below, state which students wrote it correctly. For each incorrect equation, explain the mistake.

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  9. Question 89

    1 mark · Normal

    Which element forms at the anode during the electrolysis of molten sodium bromide (NaBr)?

    1. A.Bromine
    2. B.Sodium
    3. C.Hydrogen
    4. D.Oxygen
    Answer and check →
  10. Question 90

    2 marks · Normal

    Complete the ionic half-equations for the electrolysis of molten copper(II) bromide. Include state symbols.

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