A student puts damp blue litmus paper into a test tube of gas. The paper turns red but is not bleached. Which conclusion is best supported by this result?
The gas is chlorine, because the paper changed colour.
The gas is oxygen, because the paper was not bleached.
The gas is not chlorine, because there is no bleaching.
The gas is hydrogen, because hydrogen is not an acid.
40 exam-style questions on AQA GCSE Chemistry 8.2 Identification of common gases, covering 8.2.1 Test for hydrogen, 8.2.2 Test for oxygen, 8.2.3 Test for carbon dioxide, and 8.2.4 Test for chlorine. Each one has a worked solution and a mark scheme showing where the marks go.