A garden centre sells white powders labelled as "garden lime". A student is asked to check whether one of the powders contains carbonate ions, CO32−\mathrm{CO_{3}^{2-}}CO32−.
Describe a test the student could use to show that the powder contains carbonate ions. Give the result of a positive test.
The student then tests three solutions for halide ions. She adds dilute nitric acid and then silver nitrate solution to each one. The table shows the halide ion in each solution.
| Solution | Halide ion present | Colour of precipitate |
|---|---|---|
| X | chloride, Cl−\mathrm{Cl^{-}}Cl− | ? |
| Y | bromide, Br−\mathrm{Br^{-}}Br− | ? |
| Z | iodide, I−\mathrm{I^{-}}I− | ? |
Give the colour of the precipitate formed by each solution.
Name the solution that is added together with dilute hydrochloric acid to test for sulfate ions, SO42−\mathrm{SO_{4}^{2-}}SO42−.
Give the colour of the precipitate formed in a positive test for sulfate ions.
35 exam-style questions on Edexcel GCSE Chemistry 10.1 Qualitative analysis: tests for ions, covering 10.1.1 Principles of ion tests and flame tests, 10.1.2 Tests for cations and for ammonia, 10.1.3 Tests for anions, 10.1.4 Identification of ions in unknown salts, and 10.1.5 Instrumental methods of analysis. Each one has a worked solution and a mark scheme showing where the marks go.