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 80 · Easy
Question 21
2 marks · Easy
Answer and see the solution →During the electrolysis of molten sodium bromide (), write the half-equation for the reaction at the cathode. State the number of electrons gained by each sodium ion.
Question 22
2 marks · Easy
Answer and see the solution →Molten calcium iodide () is electrolysed using inert electrodes.
(a)[1 mark]Write the half-equation for the reaction that occurs at the cathode during the electrolysis of molten calcium iodide.
(b)[1 mark]Explain why iodide ions move to the anode in this process.
Question 23
1 mark · Easy
Answer and see the solution →State what is meant by: reduction, in terms of electron transfer.
Question 24
3 marks · Easy
Answer and see the solution →The diagram shows the essential parts of an apparatus for the electrolysis of molten magnesium chloride (MgCl).
(a)[1 mark]What does it mean to 'discharge' a chloride ion (Cl) at the electrode?
(b)[1 mark]State what happens to the charge of a chloride ion when it is discharged.
(c)[1 mark]Describe briefly what is formed when chloride ions are discharged at the anode.
Question 25
2 marks · Easy
Answer and see the solution →During the electrolysis of molten sodium iodide (NaI), the following half-equations occur:
For each electrode, state whether the reaction is oxidation or reduction.
(a)[1 mark]Reaction at the anode:
(b)[1 mark]Reaction at the cathode:
Question 26
2 marks · Easy
Answer and see the solution →Explain how the OILRIG mnemonic helps you decide whether a process is oxidation or reduction, using the example of an ion gaining electrons.
Question 27
3 marks · Easy
Answer and see the solution →Table 1 shows the electron profiles for three different reactions.
Table 1: Electron Transfer in Different Reactions Process Type of Particle Electron Change W Iron(III) ion gains 3 electrons X Chloride ion loses 1 electron Y Copper(II) ion gains 2 electrons (a)[1 mark]Identify the process (W, X or Y) that involves oxidation.
(b)[1 mark]State what reduction means in terms of electron transfer.
(c)[1 mark]Identify all processes (W, X or Y) that involve reduction.
Question 28
1 mark · Easy
Answer and see the solution →When an ion is 'discharged' during electrolysis, what happens to its electric charge?
Question 29
3 marks · Easy
Answer and see the solution →During the electrolysis of molten copper(II) bromide (CuBr), the following reactions occur:
(a)[1 mark]Write the half-equation for the reaction at the anode.
(b)[1 mark]State whether the anode reaction is oxidation or reduction.
(c)[1 mark]Explain your answer to (b) using electron transfer.
Question 30
2 marks · Easy
Answer and see the solution →An aluminium ion (Al) gains 3 electrons during electrolysis.
(a)[1 mark]State whether this process is oxidation or reduction.
(b)[1 mark]Explain your answer using the OILRIG mnemonic.