Which pair of solutions can not be told apart by adding sodium hydroxide solution, but can be told apart by a flame test?
Sodium chloride and potassium chloride
Sodium chloride and sodium sulfate
Copper(II) chloride and copper(II) sulfate
Iron(II) sulfate and iron(III) sulfate
52 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.