Two colourless solutions, A and B, are tested. Barium chloride solution is added to a sample of each solution. A fresh sample of each solution is then tested by adding dilute hydrochloric acid followed by barium chloride solution.
| Solution | Barium chloride added | Dilute hydrochloric acid, then barium chloride added |
|---|---|---|
| A | White precipitate | No precipitate |
| B | White precipitate | White precipitate |
Use the results to identify the solution containing sulfate ions. Explain why the first test on solution A could give a false positive result for sulfate ions.
93 exam-style questions on AQA GCSE Chemistry 8.3 Identification of ions by chemical and spectroscopic means, covering 8.3.1 Flame tests, 8.3.2 Metal hydroxides, 8.3.3 Carbonates, 8.3.4 Halides, 8.3.5 Sulfates, 8.3.6 Instrumental methods, and 8.3.7 Flame emission spectroscopy. Each one has a worked solution and a mark scheme showing where the marks go.