Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Electrolysis
198 practice questions
Topics covered
- Why things conduct electricity17 practice questions
- Passing electricity through compounds: electrolysis20 practice questions
- The electrolysis of molten compounds19 practice questions
- Electrolysis and redox19 practice questions
- The electrolysis of other molten substances19 practice questions
- The electrolysis of aqueous solutions18 practice questions
- The electrolysis of sodium chloride solution19 practice questions
- The electrolysis of copper(ii) sulfate solution using inert electrodes18 practice questions
- The electrolysis of some other solutions using inert electrodes19 practice questions
- What would happen with non-electrolytes?19 practice questions
Practice questions
41–50 of 85 · Normal
Question 41
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 42
2 marks · Normal
Answer and see the solution →Describe two essential steps you must take to safely set up apparatus for investigating the electrolysis of concentrated sodium chloride solution in the laboratory.
Question 43
4 marks · Normal
Answer and see the solution →Concentrated sodium chloride solution is electrolysed using carbon electrodes.
(a)[1 mark]Name the product formed at the cathode.
(b)[1 mark]Name the product formed at the anode.
(c)[1 mark]Write a word or balanced symbol equation for the half-equation at the cathode.
(d)[1 mark]Write a word or balanced symbol equation for the half-equation at the anode.
Question 44
3 marks · Normal
Answer and see the solution →When electrolysing concentrated sodium chloride solution, a student expected to collect 10 cm³ of gas at each electrode. However, only 6 cm³ of chlorine gas was collected at the anode. Calculate the percentage of chlorine gas lost, and explain a possible reason for this observation.
Question 45
3 marks · Normal
Answer and see the solution →Explain why it is important not to completely cover the electrodes with the test tubes when setting up the apparatus to investigate the electrolysis of aqueous sodium chloride solution.
Question 46
4 marks · Normal
Answer and see the solution →A student electrolyses concentrated sodium chloride solution for several minutes and records the following results:
Volume of gases collected at electrodes during electrolysis Electrode Gas Volume collected (cm³) Cathode Hydrogen 20 Anode Chlorine 14 (a)[1 mark]State the product collected at the cathode.
(b)[1 mark]State the product collected at the anode.
(c)[1 mark]Suggest a reason why less chlorine was collected than hydrogen.
(d)[1 mark]Explain how the results could be used to confirm the identity of the hydrogen gas.
Question 47
1 mark · Normal
Answer and check →Which statement best explains why less chlorine gas is collected at the anode than expected when electrolysing concentrated sodium chloride solution?
- A.The chlorine evaporates quickly.
- B.Water reacts with the chlorine to make sodium hydroxide.
- C.Some chlorine dissolves in the solution.
- D.Chloride ions are less reactive than sodium ions.
Question 48
2 marks · Normal
Answer and see the solution →Give two observations you could make during the electrolysis of concentrated sodium chloride solution that would indicate a reaction is taking place.
Question 49
4 marks · Normal
Answer and see the solution →Describe the products formed at the electrodes during the electrolysis of concentrated sodium chloride solution, and test how you could confirm their presence.
(a)[2 marks]State the product formed at the cathode and describe its relevant test.
(b)[2 marks]State the product formed at the anode and describe its relevant test.
Question 50
2 marks · Normal
Answer and see the solution →During the electrolysis of sodium chloride solution, hydrogen gas is produced at the cathode rather than sodium metal.
Explain why sodium ions do not gain electrons at the cathode, but hydrogen ions do.