# A student adds dilute hydrochloric acid to separate aqueous solutions of silver nitrate, barium chloride, and calcium nitrate. Describe the observations the student would make and explain what these observations show about the ions present in each solution.

> AQA A-Level Chemistry (7405) — 3.2.6 Reactions of ions in aqueous solution (A-Level only) · Describe · 5 marks

## Mark scheme (5 marks)

1. A white precipitate forms when dilute hydrochloric acid is added to silver nitrate solution
2. The white precipitate with silver nitrate is silver chloride, showing silver ions (Ag⁺) are present
3. No precipitate / no visible change when dilute hydrochloric acid is added to barium chloride solution
4. No precipitate / no visible change when dilute hydrochloric acid is added to calcium nitrate solution
5. The absence of a precipitate with barium chloride and calcium nitrate shows that dilute hydrochloric acid / chloride ions alone do not precipitate barium or calcium ions; a different reagent (e.g. dilute sulfuric acid) would be needed to distinguish them

## Key terms

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

## Related

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-adds-dilute-hydrochloric-acid-754366bc) · Published by Druglandscape Ltd.