Corrosion of metals
9.5What the syllabus asks of you
- State the conditions required for the rusting of iron and steel to form hydrated iron(III) oxide
- Describe how barrier methods prevent rusting by excluding oxygen or water
- State some common barrier methods, including painting, greasing and coating with plastic
- Explain sacrificial protection in terms of the reactivity series and in terms of electron loss
- Describe the use of zinc in galvanising as an example of a barrier method and sacrificial protection
Read the notes first
Chapter 9: Corrosion of metals
Drill this topic
Every question on Corrosion of metals, untimed, marked as you go.
Make a worksheet
Choose the years and how many questions, then print it with the answers on separate pages.
16 questions
1May / June 2026 · Paper 11 · Q26Show mark scheme →
A1: copper, 2: less
B1: copper, 2: more
C1: magnesium, 2: less
D1: magnesium, 2: more
Mark scheme
2Oct / Nov 2025 · Paper 11 · Q26Show mark scheme →
A✓ ✓
B✓ ✗
C✗ ✓
D✗ ✗
Mark scheme
3Oct / Nov 2025 · Paper 12 · Q26Show mark scheme →
AA piece of copper is more effective than zinc because copper does not rust.
BA piece of magnesium is more effective than zinc because magnesium is less reactive than zinc.
CThe piece of zinc provides a barrier around the entire steel car.
DThe piece of zinc provides sacrificial protection to the steel car.
Mark scheme
4May / June 2025 · Paper 11 · Q27Show mark scheme →
Aalloy formation
Bbarrier and sacrificial
Cbarrier only
Dsacrificial only
Mark scheme
5Oct / Nov 2023 · Paper 11 · Q28Show mark scheme →
AA barrier method is needed to prevent the corrosion of stainless steel.
BIron corrodes to produce hydrated iron(I) oxide.
CSacrificial protection uses a less reactive metal attached to the metal object that is being protected.
DWhen corrosion occurs, the metal loses electrons to become positive ions.
Mark scheme
6Oct / Nov 2023 · Paper 12 · Q28Show mark scheme →
AIf the coating is damaged, zinc corrodes instead of iron.
BIron is above zinc in the reactivity series.
CZinc does not react with air or with water.
DZinc forms an unreactive alloy coating with iron.
Mark scheme
7May / June 2023 · Paper 11 · Q28Show mark scheme →
A1 and 2 only
B1 and 3 only
C2 and 3 only
D1, 2 and 3
Mark scheme
8May / June 2023 · Paper 12 · Q31Show mark scheme →
A1 and 2
B1 and 3
C2 and 3
D3 only
Mark scheme
9Oct / Nov 2021 · Paper 11 · Q33Show mark scheme →
A1 and 2 only
B1 and 3 only
C2 and 3 only
D1, 2 and 3
Mark scheme
10Oct / Nov 2021 · Paper 12 · Q33Show mark scheme →
A1 and 2
B1 and 3
C2 and 4
D3 and 4
Mark scheme
11May / June 2021 · Paper 12 · Q32Also set in May / June 2021 Paper 11, Oct / Nov 2016 Paper 11Show mark scheme →
AFe2+(aq) + 2e– → Fe(s)
BFe(s) → Fe2+(aq) + 2e–
CMg2+(aq) + 2e– → Mg(s)
DMg(s) → Mg2+(aq) + 2e–
Mark scheme
12May / June 2020 · Paper 12 · Q29Also set in May / June 2020 Paper 11Show mark scheme →
AO2 only, copper, iron
BO2 only, magnesium, iron
CO2 + H2O, copper, iron
DO2 + H2O, magnesium, iron
Mark scheme
13May / June 2018 · Paper 11 · Q31Show mark scheme →
Acalcium
Bcopper
Clead
Dzinc
Mark scheme
14Oct / Nov 2017 · Paper 11 · Q29Show mark scheme →
AAg
BCu
CMg
DPb
Mark scheme
15May / June 2017 · Paper 11 · Q30Show mark scheme →
AAluminium has a coating of aluminium oxide.
BAluminium has a very low density.
CAluminium is an excellent conductor of electricity.
DAluminium is less reactive than iron.
Mark scheme
16May / June 2016 · Paper 12 · Q28Show mark scheme →
Acarbon
Bcopper
Cmagnesium
Dsulfur
Mark scheme