# Transition metals are used as catalysts in many important industrial processes. Explain why transition metals are able to act as catalysts, and give two examples of transition metals used as catalysts in named industrial processes.

> AQA A-Level Chemistry (7405) — 3.2.5 Transition metals (A-Level only) · Explain · 5 marks

## Mark scheme (5 marks)

1. Transition metals can have variable oxidation states (variable valency)
2. This allows them to accept and donate electrons during a reaction (facilitating electron transfer)
3. Named transition metal catalyst correctly identified (e.g. iron, nickel, platinum, vanadium(V) oxide / vanadium pentoxide)
4. Correct industrial process matched to first named catalyst (e.g. iron — Haber process / manufacture of ammonia; nickel — hydrogenation of vegetable oils / margarine production; platinum — catalytic converters / Ostwald process; vanadium(V) oxide — Contact process / manufacture of sulfuric acid)
5. A second, different named transition metal catalyst correctly matched to a different named industrial process

## Key terms

- [transition metals](https://www.gradenine.co.uk/glossary/transition-metals)
- [catalyst](https://www.gradenine.co.uk/glossary/catalyst)

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/transition-metals-are-used-as-catalysts-db29f975) · Published by Druglandscape Ltd.