Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
The electrolysis of aqueous solutions
18 practice questions
Practice questions
11–18 of 18
Question 11
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 12
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 13
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 14
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 15
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 16
2 marks · Hard
Answer and see the solution →Describe two essential safety precautions you must take when setting up an experiment to investigate the electrolysis of concentrated sodium chloride solution in the laboratory.
Question 17
5 marks · Hard
Answer and see the solution →A student carries out the electrolysis of concentrated sodium chloride solution using carbon electrodes as shown below.
Electrolysis of concentrated sodium chloride solution (a)[1 mark]State the product formed at the cathode.
(b)[1 mark]State the product formed at the anode.
(c)[1 mark]Write the half-equation for the reaction at the cathode.
(d)[1 mark]Write the half-equation for the reaction at the anode.
(e)[1 mark]Explain why hydrogen forms at the cathode instead of sodium.
Question 18
2 marks · Hard
Answer and see the solution →During the electrolysis of concentrated sodium chloride solution, the volume of chlorine gas collected at the anode is often less than the volume expected. Explain two reasons for this observation.