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
11–20 of 85 · Normal
Question 11
3 marks · Normal
Answer and see the solution →The diagram below represents an electrolytic cell with a solution of sodium chloride ( ) and two electrodes.
(a)[1 mark]Name the electrode where reduction occurs.
(b)[1 mark]Give the name and charge of the ions that move to the anode in this process.
(c)[1 mark]State the term used for the substance, other than electrodes, that is necessary for electrolysis to occur in this experiment.
Question 12
3 marks · Normal
Answer and see the solution →Explain why molten magnesium chloride ( ) conducts electricity, but solid magnesium chloride does not. Use your knowledge of ionic compounds and their structure.
Question 13
2 marks · Normal
Answer and see the solution →State what is meant by (a) an anion, and (b) a cation.
Question 14
4 marks · Normal
Answer and see the solution →(a)[2 marks]Describe how you would set up an experiment to investigate the electrolysis of molten sodium chloride (). Include the apparatus you would use.
(b)[1 mark]State one safety precaution that should be taken when carrying out this experiment.
(c)[1 mark]What observation would show that electrolysis is taking place?
Question 15
3 marks · Normal
Answer and see the solution →(a)[1 mark]A student investigates electrolysis using an aqueous solution of potassium iodide () and two inert electrodes.
State the name given to the compound in solution that conducts electricity in this experiment.
(b)[1 mark]Name (i) the positive electrode, and (ii) the negative electrode.
(c)[1 mark]During the experiment, which direction do the cations move in the electrolyte?
Question 16
3 marks · Normal
Answer and see the solution →Explain why covalent molecular compounds such as methane () do not conduct electricity, but aqueous ammonia () can conduct electricity. Refer to the presence or absence of ions in your answer.
Question 17
4 marks · Normal
Answer and see the solution →A student recorded observations of three substances to analyse their ability to conduct electricity in different states.
(a)[2 marks]Data about electrical conduction by different substances Substance Solid Molten Aqueous Sodium chloride no yes yes Sugar no no no Potassium nitrate no yes yes Which of these substances are ionic compounds? Explain your answer using the data.
(b)[1 mark]Suggest why sugar does not conduct electricity in any state.
(c)[1 mark]Which substance is an example of a covalent compound?
Question 18
2 marks · Normal
Answer and see the solution →State the products formed at the electrodes when molten sodium chloride is electrolysed. For each product, name the electrode where it forms.
Question 19
4 marks · Normal
Answer and see the solution →Aluminium oxide can be electrolysed when molten.
(a)[1 mark]State the names and formulas of the ions present in molten aluminium oxide.
(b)[1 mark]Write the half-equation for the reaction at the cathode.
(c)[1 mark]Write the half-equation for the reaction at the anode.
(d)[1 mark]Identify the product formed at each electrode.
Question 20
4 marks · Normal
Answer and see the solution →A student investigates the electrolysis of three different molten ionic compounds using carbon electrodes. The table below shows the ions present in each compound.
Compound Cation(s) Anion(s) Magnesium bromide (MgBr2) Mg^{2+} Br^- Potassium iodide (KI) K^+ I^- Calcium chloride (CaCl2) Ca^{2+} Cl^- (a)[1 mark]For magnesium bromide, state the product formed at the anode.
(b)[1 mark]For potassium iodide, state the product formed at the cathode.
(c)[2 marks]Write the half-equation for the reaction at the anode when calcium chloride is electrolysed.