A student investigates the reaction between excess zinc powder and dilute sulfuric acid. They want to demonstrate that the reaction produces hydrogen gas and that the sulfuric acid is fully neutralised (reaching a pH of approximately 7).
They write down the following steps for their qualitative tests:
Explain one change that should be made to Step 3 and one change that should be made to Step 4 so that the student can successfully identify the gas and confirm neutralisation.
276 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.