# A student has two unlabelled solutions. One solution contains sulfate ions and the other contains chloride ions. Describe how the student could identify which solution contains sulfate ions and which contains chloride ions. Include the expected observations for each test.

> Eduqas GCSE Chemistry — C8 Chemical analysis · Describe · 4 marks

## Mark scheme (4 marks)

1. Add dilute hydrochloric acid / acidify with dilute hydrochloric acid (to remove interfering ions / carbonates) before adding barium chloride solution
2. Add barium chloride solution to test for sulfate ions; a white precipitate forms in the solution containing sulfate ions
3. Add silver nitrate solution (in acidic conditions / after acidifying with dilute nitric acid) to test for chloride ions
4. A white / cream precipitate forms in the solution containing chloride ions when silver nitrate is added

## Key terms

- [sulfate ions](https://www.gradenine.co.uk/glossary/sulfate-ions)
- [chloride ions](https://www.gradenine.co.uk/glossary/chloride-ions)

## Related

- [Revision notes for Eduqas GCSE Chemistry](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-has-two-unlabelled-solutions-742b06ca) · Published by Druglandscape Ltd.