# Explain why potassium iodide conducts electricity when dissolved in water but does not conduct electricity when it is a solid.

> Edexcel GCSE Chemistry (1CH0) — 1.5 Ionic bonding · Explain · 4 marks

> Potassium iodide is an ionic compound used in some medical treatments. It is a white crystalline solid at room temperature.

## Mark scheme (4 marks)

1. Potassium iodide is made up of / contains ions (potassium ions and iodide ions)
2. In the solid state, the ions are held in fixed positions / cannot move
3. When dissolved in water, the ions are free to move / are released from the lattice
4. Moving ions carry charge / allow a current to flow, so the solution conducts electricity

## Key terms

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

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "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/explain-why-potassium-iodide-conducts-electricity-088302aa) · Published by Druglandscape Ltd.