A scientist analyses a sample of a mixture of salts.
A flame test on the sample gives only a yellow-orange flame. The scientist then uses flame emission spectroscopy. The table shows the results and a set of reference data.
| Substance | Wavelengths of lines (nm) |
|---|---|
| Lithium ions | 610, 671 |
| Sodium ions | 589 |
| Potassium ions | 404, 767, 770 |
| Calcium ions | 423, 616, 644 |
| Sample | 404, 589, 610, 671, 767, 770 |
Which conclusion is correct?
The sample contains only sodium ions, as the flame was yellow-orange.
The sample contains lithium ions, sodium ions and potassium ions.
The sample contains sodium ions and calcium ions but no other ions.
The sample contains lithium, sodium, potassium and calcium ions.
107 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.