Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Preventing rusting by using sacrificial protection
18 practice questions
Practice questions
11–18 of 18
Question 11
3 marks · Normal
Answer and see the solution →Rusting occurs when iron is exposed to air and water. Ships are often fitted with blocks of zinc on their hulls.
(a)[3 marks]Explain, using the ideas of oxidation and reactivity, how these zinc blocks prevent the iron hull from rusting.
Question 12
4 marks · Normal
Answer and see the solution →A scientist is choosing a metal to protect an iron water tank from rusting. She tests three metals (A, B, and C), each attached to iron and left in moist air. The results are shown below.
Results: Rusting of iron with different metals attached Metal attached Observation after 1 month A Iron is rusted; attached metal is not corroded B Iron is shiny; attached metal is heavily corroded C Iron is rusted; attached metal is also rusted (a)[2 marks]Which metal, A, B, or C, acts as a sacrificial anode for iron? Explain your answer.
(b)[2 marks]Explain, using the observations, why the chosen metal must be more reactive than iron.
Question 13
1 mark · Normal
Answer and check →Which structure is commonly protected using sacrificial anodes made of zinc or magnesium?
- A.Aluminium can
- B.Underground oil pipeline
- C.Plastic water bottle
- D.Glass window
Question 14
2 marks · Normal
Answer and see the solution →State what is meant by a sacrificial anode, and name a metal commonly used as one to protect iron.
Question 15
4 marks · Normal
Answer and see the solution →A section of an underwater steel bridge has several aluminium blocks attached to it.
(a)[2 marks]Explain why aluminium is able to protect the steel from rusting by sacrificial protection.
(b)[2 marks]Describe what happens to the aluminium blocks over time and why they are eventually replaced.
Question 16
2 marks · Hard
Answer and see the solution →Explain why a block of copper cannot be used as a sacrificial anode to protect iron from rusting.
Question 17
5 marks · Hard
Answer and see the solution →An engineer is tasked with protecting an iron pipeline buried underground using the method of sacrificial protection.
(a)[2 marks]Explain why sacrificial anodes must be made of a metal more reactive than iron.
(b)[2 marks]The engineer is considering aluminium, tin, and silver as possible metals for sacrificial anodes. Aluminium is above iron in the reactivity series, tin is just below iron, and silver is far below iron. Which of these metals could be used as sacrificial anodes for the pipeline? Justify your choice.
(c)[1 mark]Describe what happens to the chosen sacrificial anode metal over time.
Question 18
2 marks · Hard
Answer and see the solution →State one example of a structure (not previously listed in examples) that can be protected from rusting using sacrificial anodes, and name a suitable metal that could be used as the sacrificial anode for this structure.