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CAIE IGCSE Chemistry Galvanising Barrier and Sacrificial Protection

Practise explaining how a zinc coating protects iron both as an intact barrier and, when scratched, through preferential oxidation of zinc.

Syllabus
2026–2028
Course
Chemistry 0620

Exam points

  • define galvanising as coating iron or steel with a protective layer of zinc metal
  • explain intact zinc as a barrier that prevents oxygen and water reaching iron
  • explain continued protection after damage because zinc is more reactive and oxidises first

9.5.4—Use of zinc in galvanising as an question 1

[Maximum number: 1]

This question is about iron.

Iron forms rust.

Rusting is prevented by coating iron with zinc.

Name the process in which zinc is used to coat iron to prevent rusting.

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