# Iron(III) chloride (FeCl₃) is an ionic compound. When solid iron(III) chloride is dissolved in water, the resulting solution conducts electricity. Explain, in terms of particles, why solid iron(III) chloride does not conduct electricity but its aqueous solution does.

> Edexcel A-Level Chemistry (9CH0) — Topic 1 Foundations in chemistry · Explain · 5 marks

> Iron(III) chloride is formed when iron reacts with chlorine. It exists as a white-yellow crystalline solid at room temperature.

## Mark scheme (5 marks)

1. Solid iron(III) chloride contains ions held in a fixed lattice / regular arrangement
2. Because the ions cannot move (in the solid), electrical charge cannot be carried
3. When dissolved in water, the ionic lattice breaks down / the compound dissociates
4. The ions (Fe³⁺ and Cl⁻) are free to move throughout the solution
5. Moving ions carry electrical charge through the solution, allowing it to conduct

## Key terms

- [ionic compound](https://www.gradenine.co.uk/glossary/ionic-compound)
- [conducts electricity](https://www.gradenine.co.uk/glossary/conducts-electricity)
- [aqueous solution](https://www.gradenine.co.uk/glossary/aqueous-solution)

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](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/iron-iii-chloride-fecl-is-an-ionic-caa00185) · Published by Druglandscape Ltd.