# State and explain why silver is used to make electrical contacts in high-quality switches, and why zinc is used to coat steel in the process known as galvanising. Give one reason for each use.

> Cambridge International IGCSE Chemistry (0620) — 9.2 Uses of metals · State and explain · 4 marks

## Mark scheme (4 marks)

1. Silver is a good conductor of electricity / heat
2. This allows electric current to pass through the contact / circuit easily with minimal energy loss
3. Zinc is more reactive than iron / steel (so acts as a sacrificial metal)
4. Zinc corrodes / oxidises preferentially, protecting the steel beneath from rusting even if the zinc layer is scratched

## 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 "State and explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/state-and-explain-why-silver-is-7ecc0c7d) · Published by Druglandscape Ltd.