A school technician finds some bottles of metal salt solutions with faded labels. She adds a few drops of sodium hydroxide solution to a sample of each solution.
One solution forms a blue precipitate. Name the metal ion in this solution.
Give the colour of the precipitate formed when sodium hydroxide solution is added to a solution containing iron(III) ions, Fe3+\mathrm{Fe^{3+}}Fe3+.
Give the colour of the precipitate formed when sodium hydroxide solution is added to a solution containing iron(II) ions, Fe2+\mathrm{Fe^{2+}}Fe2+.
Another solution contains ammonium ions, NH4+\mathrm{NH_{4}^{+}}NH4+. When this solution is warmed with sodium hydroxide solution, a gas is given off.
Name this gas.
Describe the test for this gas and give the positive 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.