Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Principles of Chemistry
991 practice questions
Topics covered
- States of Matter102 practice questions
- Elements, Compounds and Mixtures69 practice questions
- Atomic Structure108 practice questions
- The Periodic Table103 practice questions
- Chemical Formulae, Equations and Calculations Part 119 practice questions
- Chemical Formulae, Equations and Calculations Part 2144 practice questions
- Ionic Bonding143 practice questions
- Covalent Bonding68 practice questions
- Metallic Bonding19 practice questions
- Electrolysis198 practice questions
Practice questions
141–150 of 161 · Hard
Question 141
2 marks · Hard
Answer and see the solution →Write the ionic half-equation for the reaction that occurs at the cathode during the electrolysis of molten magnesium oxide (MgO).
Question 142
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 143
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 144
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.
Question 145
2 marks · Hard
Answer and see the solution →Write a balanced half-equation, including state symbols, for the reduction that takes place at the cathode during the electrolysis of sodium chloride solution. State the physical state of each species involved.
Question 146
5 marks · Hard
Answer and see the solution →A student sets up an electrolytic cell using sodium chloride solution and collects the gases produced. They notice that the solution near the cathode becomes increasingly alkaline as the reaction proceeds.
(a)[1 mark]Name the ion that increases in concentration around the cathode.
(b)[2 marks]Write a balanced chemical equation, with state symbols, for the process at the cathode that explains this change.
(c)[2 marks]Explain why the solution near the cathode becomes alkaline as electrolysis continues. Relate your answer to the ions produced and removed at the electrode.
Question 147
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 148
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 149
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 150
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.