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 80 · Easy
Question 41
2 marks · Easy
Answer and see the solution →During the electrolysis of concentrated sodium chloride solution, a total of 8 cm³ of gas is collected at the cathode. The experiment is carried out at room temperature and pressure.
(a)[1 mark]Name the product formed at the cathode.
(b)[1 mark]What volume of chlorine gas would you expect to collect at the anode under the same conditions?
Question 42
2 marks · Easy
Answer and see the solution →A student finds that the volume of chlorine gas collected during the electrolysis of concentrated sodium chloride solution is less than expected.
(a)[1 mark]Explain why less chlorine gas is collected than expected.
(b)[1 mark]Suggest one way you could change the experiment to collect more chlorine gas.
Question 43
1 mark · Easy
Answer and see the solution →Name one piece of apparatus you would need to collect the gas produced at the cathode during the electrolysis of concentrated sodium chloride solution.
Question 44
3 marks · Easy
Answer and see the solution →The electrolysis of concentrated sodium chloride solution is carried out using carbon electrodes.
(a)[1 mark]State the product formed at the cathode.
(b)[1 mark]State the product formed at the anode.
(c)[1 mark]Write a word equation for the reaction that occurs at the anode.
Question 45
2 marks · Easy
Answer and see the solution →In an experiment, 12 cm³ of hydrogen gas is collected at the cathode during the electrolysis of concentrated sodium chloride solution. The theoretical volume of chlorine expected at the anode is also 12 cm³, but only 7 cm³ is collected.
Calculate the difference between the expected and the actual volume of chlorine collected. Explain why there is this difference.
Question 46
1 mark · Easy
Answer and see the solution →During the electrolysis of sodium chloride solution, what ion builds up near the cathode making the solution there alkaline?
Question 47
3 marks · Easy
Answer and see the solution →A student electrolyses sodium chloride solution and is surprised that hydrogen, not sodium, is produced at the cathode.
(a)[1 mark]Name the two positive ions present in the solution that could be discharged at the cathode.
(b)[1 mark]State which of these ions is discharged and forms a gas at the cathode.
(c)[1 mark]Explain why sodium ions are not discharged at the cathode.
Question 48
2 marks · Easy
Answer and see the solution →Write a balanced half-equation for the cathode reaction during the electrolysis of sodium chloride solution when hydrogen gas is formed.
Question 49
2 marks · Easy
Answer and see the solution →Describe why the region near the cathode becomes alkaline during the electrolysis of sodium chloride solution.
Question 50
3 marks · Easy
Answer and see the solution →The table shows the tendency to gain electrons (ease of reduction) for some ions in decreasing order.
Reduction Tendency of Some Ions Ion Reduction Tendency K^+ Very difficult Na^+ Very difficult Ca^2+ Difficult H^+ Easier Cu^2+ Very easy A student electrolyses sodium chloride solution. Use the data to answer the following questions.
(a)[1 mark]Suggest which ion, Na⁺ or H⁺, is more easily reduced at the cathode.
(b)[1 mark]Which gas is formed at the cathode?
(c)[1 mark]Explain why sodium metal does not form at the cathode, using the reduction tendency data.