A student is given four solutions, W, X, Y and Z. Each solution contains one metal ion. The student carries out a flame test on each solution.
The table shows the results.
| Solution | Flame colour |
|---|---|
| W | yellow |
| X | orange-red |
| Y | lilac |
| Z | red |
Name the metal ion in solution X and in solution Z.
The student used the same wire loop for every test. Explain why the loop must be cleaned between each test.
A fifth solution contains a mixture of sodium ions and potassium ions. The flame test only shows a yellow flame.
Explain why a flame test cannot show that potassium ions are present in this mixture.
A test used to identify an ion must give a unique result. Explain why.
Describe a test, other than a flame test, that could be used to confirm the metal ion in solution X. Give the result.
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.