Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Electrolysis and redox
19 practice questions
Practice questions
1–8 of 8 · Easy
Question 1
1 mark · Easy
Answer and see the solution →State what is meant by: reduction, in terms of electron transfer.
Question 2
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 3
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 4
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 5
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 6
1 mark · Easy
Answer and see the solution →When an ion is 'discharged' during electrolysis, what happens to its electric charge?
Question 7
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 8
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.