Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
The electrolysis of other molten substances
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →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.
Question 12
3 marks · Normal
Answer and see the solution →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.
Question 13
4 marks · Normal
Answer and see the solution →Student equations for the electrolysis of molten calcium bromide Student Cathode equation Anode equation A Ca^{2+} + 2e^- \to Ca 2Br^- \to Br_2 + 2e^- B Ca^{2+} \to Ca + 2e^- Br^- \to Br_2 + 2e^- C Ca^{2+} + e^- \to Ca 2Br^- \to Br_2 + 2e^- D Ca^{2+} + 2e^- \to Ca 2Br^- \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.
Question 14
1 mark · Normal
Answer and check →Which element forms at the anode during the electrolysis of molten sodium bromide (NaBr)?
- A.Bromine
- B.Sodium
- C.Hydrogen
- D.Oxygen
Question 15
2 marks · Normal
Answer and see the solution →Complete the ionic half-equations for the electrolysis of molten copper(II) bromide. Include state symbols.
Question 16
4 marks · Normal
Answer and see the solution →This question is about the electrolysis of molten tin(II) chloride (SnCl2).
(a)[2 marks]Write the balanced ionic half-equation for the reaction at the cathode.
(b)[2 marks]Write the balanced ionic half-equation for the reaction at the anode.
Question 17
2 marks · Hard
Answer and see the solution →Balance the following ionic half-equation for the electrolysis of a molten ionic compound, so that both the number of atoms and the charges are equal on both sides:
where M represents a generic metal.
Question 18
5 marks · Hard
Answer and see the solution →A molten ionic compound XY is electrolysed using inert electrodes.
(a)[2 marks]State which element is produced at the cathode. Explain your answer.
(b)[2 marks]State which element is produced at the anode. Explain your answer.
(c)[1 mark]Give one reason why these predictions are valid only for molten binary ionic compounds, not aqueous ones.
Question 19
2 marks · Hard
Answer and see the solution →Write the ionic half-equation for the reaction that occurs at the cathode during the electrolysis of molten magnesium oxide (MgO).