This question is about chemical analysis of inorganic salts.
A student investigated sodium sulfate solution and calcium chloride solution using a series of qualitative tests, including flame tests.
This is the method used for the flame tests:
Identify the characteristic flame colour produced by the sodium sulfate solution.
Calcium compounds normally produce a distinct orange-red flame colour. Explain why the student's method failed to produce a distinct orange-red flame colour when testing the calcium chloride solution.
In a separate set of tests, the student added sodium hydroxide solution dropwise until in excess to:
Describe the observations for each of these two tests.
To test for the presence of sulfate ions, the student first acidified the sodium sulfate solution with dilute hydrochloric acid. State the name of the reagent that should be added next to confirm the presence of sulfate ions.
To test for the presence of chloride ions, the student acidified the calcium chloride solution with dilute nitric acid. Name the reagent added to show the presence of chloride ions, and state the observation that confirms their presence.
29 exam-style questions on AQA GCSE Chemistry 8.3 Identification of ions by chemical and spectroscopic means, covering 8.3.1 Flame tests, 8.3.2 Metal hydroxides, 8.3.3 Carbonates, 8.3.4 Halides, 8.3.5 Sulfates, 8.3.6 Instrumental methods, and 8.3.7 Flame emission spectroscopy. Each one has a worked solution and a mark scheme showing where the marks go.