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
71–80 of 198
Question 71
2 marks · Normal
Answer and see the solution →For the electrolysis of molten calcium bromide (CaBr_2):
(a)[1 mark]Which electrode (anode or cathode) is the site of oxidation?
(b)[1 mark]Which electrode reaction involves reduction?
Question 72
4 marks · Normal
Answer and see the solution →You are asked to explain how the OILRIG mnemonic helps when deciding whether a reaction is oxidation or reduction.
(a)[2 marks]Write what each letter in OILRIG stands for.
(b)[1 mark]Use the mnemonic to decide whether the following process is oxidation or reduction: Fe^{2+} gains 2 electrons to form Fe.
(c)[1 mark]State how the mnemonic helps you to answer part (b).
Question 73
2 marks · Hard
Answer and see the solution →Define oxidation and reduction in terms of electron transfer. Give your answers using complete sentences.
Question 74
5 marks · Hard
Answer and see the solution →The apparatus below is used to electrolyse molten tin(II) chloride (SnCl₂). Tin(II) ions (Sn²⁺) and chloride ions (Cl⁻) move towards the electrodes and react.
Electrolysis setup for molten tin(II) chloride (a) State what is meant by 'discharging' a tin(II) ion during the electrolysis of molten tin(II) chloride.
(a)[2 marks]State what is meant by 'discharging' a tin(II) ion during the electrolysis of molten tin(II) chloride.
(b)[2 marks]Explain, in terms of electron transfer, what happens to a tin(II) ion at the cathode in this process.
(c)[1 mark]Write a half-equation for the reaction involving tin(II) ions at the cathode.
Question 75
2 marks · Hard
Answer and see the solution →The electrolysis of molten iron(III) chloride (FeCl₃) involves reactions at both electrodes.
State which electrode reaction involves oxidation, and which involves reduction. Explain your answer with reference to loss or gain of electrons.
Question 76
1 mark · Easy
Answer and see the solution →State which element forms at the anode during the electrolysis of molten magnesium oxide.
Question 77
3 marks · Easy
Answer and see the solution →The electrolysis of molten zinc(II) chloride produces two substances at the electrodes.
(a)[1 mark]Write the ionic half-equation for the reaction at the cathode.
(b)[1 mark]Write the ionic half-equation for the reaction at the anode.
(c)[1 mark]State which type of particle (cation or anion) moves towards the cathode.
Question 78
2 marks · Easy
Answer and see the solution →Balance the following ionic half-equation for the electrolysis of molten calcium chloride so that both atoms and charges balance:
Question 79
2 marks · Easy
Answer and see the solution →Explain why sodium, and not chlorine, is formed at the cathode during the electrolysis of molten sodium chloride.
Question 80
3 marks · Easy
Answer and see the solution →A student studies the electrolysis of three molten ionic compounds.
Results of Electrolysis Compound Element at Cathode Element at Anode Magnesium fluoride ? Fluorine Lead(II) bromide Lead ? Potassium iodide ? Iodine (a)[1 mark]Complete the table by naming the element formed at the cathode for magnesium fluoride.
(b)[1 mark]Name the element formed at the anode for lead(II) bromide.
(c)[1 mark]Name the element formed at the cathode for potassium iodide.