A conservator is checking soluble salts washed from the surface of a ceramic object. An earlier test showed that carbonate ions are present in the wash water.
The conservator carries out three tests using fresh liquids.
| Test | Liquid tested | Reagents added in order | Observation |
|---|---|---|---|
| 1 | wash water | silver nitrate solution | a precipitate forms |
| 2 | wash water | dilute nitric acid, then silver nitrate solution | a yellow precipitate forms |
| 3 | distilled water containing no dissolved salts | dilute hydrochloric acid, then silver nitrate solution | a white precipitate forms |
Explain how the results identify the halide ion in the wash water and why the procedure in test 2 is valid. Refer to all three tests in your answer.
107 exam-style questions on OCR GCSE Chemistry 4.2 Identifying the products of chemical reactions, covering 4.2.1 Tests to identify gases, 4.2.2 Tests for aqueous ions and flame tests, and 4.2.3 Instrumental methods of analysis. Each one has a worked solution and a mark scheme showing where the marks go.