A technician monitors a nutrient solution used to grow plants. A flame test on the solution gives a yellow flame.
The technician then uses flame emission spectroscopy. The tables show some characteristic line positions for four metal ions and the line positions detected in the nutrient solution.
| Metal ion | Characteristic line positions in nm |
|---|---|
| Lithium | 610, 671 |
| Sodium | 589 |
| Potassium | 404, 766 |
| Calcium | 423, 616 |
| Line positions detected in the nutrient solution in nm |
|---|
| 404 |
| 589 |
| 766 |
Use the results to explain why the flame test gives incomplete information about the metal ions in the solution.
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.