A student wants to identify the ions contained in an unknown solid, Z.
She dissolves the solid in distilled water and performs a series of qualitative tests on the resulting solution.
The table below shows her experimental results:
| Test | Method | Observations |
|---|---|---|
| Test 1 | Flame test | Lilac flame seen |
| Test 2 | Add dilute sodium hydroxide solution | Blue precipitate forms |
| Test 3 | Add dilute nitric acid, then silver nitrate solution | White precipitate forms |
| Test 4 | Add dilute hydrochloric acid, and bubble any gas produced through limewater | Effervescence is observed and the limewater turns cloudy |
Describe how the student should carry out the flame test in Test 1 to obtain a reliable result.
The student concludes that solid Z contains only copper(II) ions, Cu2+\text{Cu}^{2+}Cu2+, and chloride ions, Cl−\text{Cl}^-Cl−.
Use her experimental results to explain whether her conclusion is correct.
41 exam-style questions on OCR GCSE Chemistry Identifying the products of chemical reactions. Each one has a worked solution and a mark scheme showing where the marks go.