CAIE IGCSE Chemistry: Copper Sulfate Electrolysis Question Bank

Practise comparing copper(II) sulfate electrolysis with inert and copper electrodes through products, observations and ion changes.

Exam points

predict copper at the cathode and oxygen bubbles at the anode with inert electrodes
explain why the blue copper(II) sulfate solution fades when copper ions are discharged
compare copper electrodes: anode dissolves while copper is deposited at the cathode

[Maximum number: 3]

This question is about electricity and chemical reactions.

(a)

Aqueous copper(II) sulfate is an electrolyte.

The electrolysis of aqueous copper(II) sulfate using inert electrodes forms:
- copper at the cathode
- oxygen at the anode.

[ 2 ]

(i)

State what happens to the colour of the aqueous copper(II) sulfate as this electrolysis progresses.

[ 1 ]

(ii)

Give the formula of the ion that forms oxygen at the anode.

[ 1 ]

$\mathrm{OH}^{-}$

(b)

The electrolysis of aqueous copper(II) sulfate is repeated using copper electrodes.

State what happens to the anode.

[ 1 ]

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4.1.9—Products formed at the electrodes and question 1

Question (a)

Question (i)

Question (ii)

Question (b)