A quality-control chemist checks three samples taken from separate gas cylinders. Each sample contains hydrogen, oxygen, carbon dioxide or chlorine.
The chemist holds dry blue litmus paper in the first sample. The paper does not change colour. Explain why this result does not rule out chlorine.
A glowing splint is lowered into the second sample. The splint relights. Give the identity of the gas indicated by this observation.
The third sample is bubbled through limewater. The limewater becomes milky. Name the solid that causes the milkiness.
89 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.