A technician has three solutions, X, Y and Z.
Each solution contains one of these compounds: sodium carbonate, sodium iodide, sodium sulfate.
The technician does three tests on each solution.
The table shows the results.
| Test | Solution X | Solution Y | Solution Z |
|---|---|---|---|
| add dilute hydrochloric acid | fizzes | no change | no change |
| add dilute nitric acid, then silver nitrate solution | fizzes, then no precipitate | yellow precipitate | no precipitate |
| add dilute hydrochloric acid, then barium chloride solution | fizzes, then no precipitate | no precipitate | white precipitate |
Identify the compound in each solution.
Solution X gives off a gas when dilute hydrochloric acid is added.
Describe the test for this gas. Give the result of the test.
Explain why dilute nitric acid, and not dilute hydrochloric acid, is added before the silver nitrate solution.
Predict the result of the silver nitrate test if solution Y had contained sodium bromide instead.
52 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.