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Chemguide Support for Edexcel IGCSE Chemistry |
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Extra material needed for the 2010 exam - Chapter 9 This page lists the material from the old Edexcel syllabus which isn't covered by my new Edexcel IGCSE Chemistry book. Reacting acids with sulfites This follows neatly on from the reactions between acids and carbonates on page 75. The equations are very similar. Sulfites react with acids to give a salt, sulfur dioxide and water. For example, if you add some white sodium sulphite crystals to dilute hydrochloric acid, a gas is evolved, and you get a colourless solution of sodium chloride formed.
Or, the ionic form:
The sulfur dioxide is a poisonous, acrid smelling gas. It is acidic (turns blue litmus paper red), and is tested using potassium dichromate paper. This orange paper turns green in the presence of sulfur dioxide. The chemistry of this test is beyond GCSE. Return to complete list of extras © Jim Clark 2009 |
