A gas sample may contain hydrogen or oxygen. During a demonstration, a burning splint is held at the open end of a test tube containing the gas. A squeaky pop is heard, but there is no colour change. An observer claims that the result cannot identify hydrogen because there was no colour change. Why is this claim wrong?
Hydrogen is identified only when a glowing splint bursts into flame.
The squeaky pop is caused by the splint, so it cannot identify the gas.
Hydrogen is identified by the squeaky pop; no colour change is expected.
No colour change shows that oxygen was present with the hydrogen.
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.