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
51–60 of 80 · Easy
Question 51
1 mark · Easy
Answer and see the solution →What is the symbol equation for the reduction of hydrogen ions at the cathode during electrolysis of sodium chloride solution?
Question 52
3 marks · Easy
Answer and see the solution →During the electrolysis of sodium chloride solution, a student notices the solution near the cathode becomes alkaline.
(a)[1 mark]Name the ion that increases in concentration near the cathode.
(b)[1 mark]Write the half-equation that shows the production of hydrogen gas at the cathode.
(c)[1 mark]Explain why the increase of this ion causes the solution to become alkaline.
Question 53
2 marks · Easy
Answer and see the solution →At the cathode during the electrolysis of sodium chloride solution, two different possible ions could gain electrons. Use the position of sodium and hydrogen in the reactivity series to deduce which ion is discharged.
Question 54
1 mark · Easy
Answer and see the solution →State the product formed at the cathode during the electrolysis of copper(II) sulfate solution using inert electrodes.
Question 55
2 marks · Easy
Answer and see the solution →The reactivity series places copper below hydrogen. Using this fact and your knowledge of ions in copper(II) sulfate solution, explain why copper is deposited at the cathode and not hydrogen during electrolysis with inert electrodes.
Question 56
2 marks · Easy
Answer and see the solution →Describe how a sample of copper(II) sulfate solution would be different after it is electrolysed for a long time using inert electrodes.
Question 57
3 marks · Easy
Answer and see the solution →The table below shows the ions present in copper(II) sulfate solution before and after electrolysis with inert electrodes.
Ion Before electrolysis After prolonged electrolysis Cu^{2+} Present Absent SO_4^{2-} Present Present H^+ Present Present OH^- Present Absent From the table, state which ion is responsible for the product formed at the cathode, and name the product.
From the table, state which ion is responsible for the product formed at the anode, and name the product.
Using your answers, give the overall effect of electrolysis on the copper(II) sulfate solution.
Question 58
1 mark · Easy
Answer and see the solution →Write the balanced half-equation for the reaction at the cathode during the electrolysis of copper(II) sulfate solution using inert electrodes.
Question 59
3 marks · Easy
Answer and see the solution →Explain why oxygen is produced at the anode and not sulfate ions are discharged during the electrolysis of copper(II) sulfate solution with inert electrodes.
Question 60
2 marks · Easy
Answer and see the solution →If all the copper(II) ions are removed from 100 mL of copper(II) sulfate solution by electrolysis with inert electrodes, explain and calculate what type of ions are left in the solution and what the new solution is.