Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
The electrolysis of aqueous solutions
18 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
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 2
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 3
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 4
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 5
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 6
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 7
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 8
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.