# Explain why potassium iodide (KI) dissolves readily in water but does not conduct electricity as a solid.

> IB DP Chemistry Standard Level (2023 syllabus) — S2.1 The ionic model · Explain · 4 marks

## Mark scheme (4 marks)

1. KI is an ionic compound consisting of K⁺ and I⁻ ions held together by strong electrostatic attractions in a lattice
2. Water molecules (polar/with partial charges) attract and surround the ions, breaking the ionic lattice apart — the ions become dispersed/hydrated in solution
3. In solution the ions are free to move, allowing charge to be carried — KI solution conducts electricity
4. In the solid state the ions are fixed/held rigidly in the lattice and cannot move, so solid KI cannot conduct electricity

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- [Revision notes for IB DP Chemistry Standard Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
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