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
21–30 of 33 · Hard
Question 21
2 marks · Hard
Answer and see the solution →Explain why sodium ions are not discharged at the cathode during the electrolysis of sodium chloride solution, whereas hydrogen is.
Question 22
2 marks · Hard
Answer and see the solution →Write the balanced half-equation for the reaction that takes place at the anode during the electrolysis of copper(II) sulfate solution using inert electrodes.
Question 23
5 marks · Hard
Answer and see the solution →A student performs the electrolysis of copper(II) sulfate solution using inert electrodes. Answer the following questions about the products at the electrodes.
(a)[1 mark]State the product formed at the cathode.
(b)[1 mark]State the product formed at the anode.
(c)[2 marks]Describe how you can identify the product formed at the anode during the electrolysis.
(d)[1 mark]What would you observe on the cathode after the electrolysis has run for a few minutes?
Question 24
2 marks · Hard
Answer and see the solution →Write the balanced half-equation for the reaction that takes place at the cathode when copper(II) sulfate solution is electrolysed using inert electrodes.
Question 25
2 marks · Hard
Answer and see the solution →An aqueous solution of zinc sulfate is electrolysed using inert electrodes.
State whether hydrogen or zinc is produced at the cathode. Explain your answer using the reactivity series.
Question 26
5 marks · Hard
Answer and see the solution →A student electrolyses separate aqueous solutions containing different anions using inert electrodes.
(a)[1 mark]State which ion produces oxygen gas at the anode when an aqueous solution of sodium sulfate is electrolysed.
(b)[2 marks]Explain why oxygen is produced at the anode during this electrolysis and not another gas.
(c)[2 marks]During the electrolysis of aqueous sodium chloride with inert electrodes, state the product formed at the anode. Explain your answer.
Question 27
2 marks · Hard
Answer and see the solution →Predict the products formed at the electrodes when an aqueous solution of copper(II) bromide is electrolysed using inert electrodes.
State the product formed at:
(a)[1 mark]the cathode
(b)[1 mark]the anode
Question 28
2 marks · Hard
Answer and see the solution →A student tries to electrolyse solid iodine and observes no current flows through the circuit. The student then dissolves the iodine in water and tries again, but the bulb still does not light. State and explain what these results show about the electrical properties and bonding type of iodine.
Question 29
5 marks · Hard
Answer and see the solution →A student investigates the electrical conductivity of three white solids: compound A, compound B and compound C. The student tests each substance (i) as a solid, (ii) after dissolving it in water, and (iii) after melting it. The observations are recorded below:
Conductivity results for three compounds Substance Solid Aqueous solution Molten Compound A Does not conduct Does not conduct Does not conduct Compound B Does not conduct Conducts Conducts Compound C Does not conduct Does not conduct Conducts (a)[4 marks]For each compound (A, B and C), state whether it is ionic, covalent (non-electrolyte), or another type. Give a reason for each answer.
(b)[1 mark]Suggest a familiar example of a substance that would behave in the same way as compound A.
Question 30
2 marks · Hard
Answer and see the solution →A student is investigating whether a white crystalline solid is an ionic compound or a covalent compound. The student finds that the solid does not conduct electricity, and that dissolving the solid in water still does not allow the solution to conduct electricity. State what type of compound the solid is and explain your reasoning.