A student writes four statements about the tests for hydrogen and carbon dioxide.
Statement 1: a gas that puts out a lit splint must be carbon dioxide
Statement 2: the squeaky pop is heard because hydrogen reacts rapidly with oxygen in the air to form water
Statement 3: if a gas is bubbled through limewater and the limewater stays clear, the gas must be hydrogen
Statement 4: limewater turns milky because an insoluble solid, calcium carbonate, forms
Which statements are correct?
2 and 4 only
1 and 3 only
2, 3 and 4 only
1, 2 and 4 only
44 exam-style questions on Edexcel GCSE Chemistry 4.1 Acids, covering 4.1.1 Acids, alkalis and the pH scale, 4.1.2 Hydrogen ion concentration and pH, 4.1.3 Dilute and concentrated, weak and strong acids, 4.1.4 Bases, alkalis and the reactions of acids, 4.1.5 Chemical tests for hydrogen and carbon dioxide, 4.1.6 Neutralisation as a reaction of acids with bases, 4.1.7 Preparing soluble salts, and 4.1.8 Solubility rules and preparing insoluble salts. Each one has a worked solution and a mark scheme showing where the marks go.