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CAIE IGCSE Chemistry Electrochemistry Questions

Practise electrolysis, electrode products, half-equations, electroplating and hydrogen fuel cells across the CAIE IGCSE Chemistry electrochemistry unit.

Syllabus
2026–2028
Course
Chemistry 0620

Covered syllabus points

4.1 Electrolysis4.2 Hydrogen–oxygen fuel cells

4. Electrochemistry question 1

[Maximum number: 8]

This question is about chemical reactions and electricity.

Question (a)

(a)

The diagram shows the apparatus used in the production of electrical energy in a simple cell.

Figure for Question (a) — CAIE IGCSE Chemistry

The zinc electrode dissolves in the electrolyte forming Zn2+(aq)\mathrm{Zn}^{2+}(\mathrm{aq}) ions.

[ 1 ]

Question (i)

(i)

Draw an arrow on the diagram to show the direction of electron flow.

[ 1 ]

Question (b)

(b)

Fuel cells are used to generate electricity.

[ 2 ]

Question (i)

(i)

Name the reactants in a fuel cell.

[ 1 ]

Question (ii)

(ii)

Name the waste product of a fuel cell.

[ 1 ]

Question (c)

(c)

Electricity can be used to break down aqueous or molten ionic compounds.

[ 1 ]

Question (i)

(i)

Name the process which uses electricity to break down aqueous or molten ionic compounds.

[ 1 ]

Question (d)

(d)

Brine is concentrated aqueous sodium chloride.

[ 4 ]

Question (i)

(i)

Name three substances which are manufactured by passing electricity through brine.

1
2

3

[ 3 ]

Question (ii)

(ii)

Name a different substance formed when molten sodium chloride is used instead of concentrated aqueous sodium chloride.

[ 1 ]

4. Electrochemistry question 2

[Maximum number: 13]

This question is about electricity and chemical reactions.

Question (a)

(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.

[ 6 ]

Question (i)

(i)

State what is meant by the term electrolyte.

[ 2 ]

Question (ii)

(ii)

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

[ 1 ]

Question (iii)

(iii)

Write an ionic half-equation for the formation of copper at the cathode.

[ 2 ]

Question (iv)

(iv)

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

[ 1 ]

Question (b)

(b)

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

State what happens to the anode.

[ 1 ]

Question (c)

(c)

Spoons can be electroplated with silver.

[ 5 ]

Question (i)

(i)

Name the substances used as:
the anode (positive electrode)
the cathode (negative electrode)
the electrolyte.

[ 3 ]

Question (ii)

(ii)

State two reasons why spoons are electroplated.

1

2

[ 2 ]

Question (d)

(d)

Hydrogen-oxygen fuel cells can be used to produce electricity to power cars. Petrol produces carbon dioxide and carbon monoxide when it powers cars.

[ 1 ]

Question (i)

(i)

State one disadvantage, other than cost, of using hydrogen-oxygen fuel cells to power cars compared to using petrol.

[ 1 ]
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