# Lithium, sodium and potassium are all alkali metals. When sodium is added to water, it reacts vigorously to produce a gas and a solution with a pH greater than 7. State the name of the gas produced and the name of the solution formed when sodium reacts with water. Explain why the solution formed is alkaline.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 2.1 Group 1 (alkali metals) · State · 4 marks

> The alkali metals in Group 1 all react with water. Sodium reacts more vigorously than lithium but less vigorously than potassium.

## Mark scheme (4 marks)

1. The gas produced is hydrogen
2. The solution formed is sodium hydroxide
3. Sodium hydroxide dissociates / dissolves in water to produce hydroxide ions (OH⁻)
4. Solutions with a pH greater than 7 are alkaline / hydroxide ions cause the pH to be above 7

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel International GCSE Chemistry (4CH1)](https://www.gradenine.co.uk/learn)
- [How to answer "State" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/lithium-sodium-and-potassium-are-all-340f559f) · Published by Druglandscape Ltd.