# Describe how galvanising protects iron from rusting, and explain why this protection continues even if the zinc coating is scratched to expose the iron beneath.

> Cambridge International IGCSE Chemistry (0620) — 9.5 Corrosion of metals · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. Galvanising involves coating iron with a layer of zinc
2. The zinc layer acts as a barrier, preventing oxygen and water from reaching the iron surface
3. Zinc is more reactive than iron / zinc is higher than iron in the reactivity series
4. Zinc corrodes (oxidises/reacts) in preference to the iron, so the iron remains protected — this is sacrificial protection

## Key terms

- [galvanising](https://www.gradenine.co.uk/glossary/galvanising)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-galvanising-protects-iron-from-0e33bf09) · Published by Druglandscape Ltd.