A technician investigates a solution containing chloride ions. The solution is electrolysed using inert electrodes. The gas formed at the positive electrode turns damp blue litmus paper red and then bleaches it white.
A trainee concludes that the gas is oxygen because it is formed at the positive electrode. Explain why this conclusion is not supported by the evidence. Include why the litmus paper must be damp.
107 exam-style questions on OCR GCSE Chemistry 4.2 Identifying the products of chemical reactions, covering 4.2.1 Tests to identify gases, 4.2.2 Tests for aqueous ions and flame tests, and 4.2.3 Instrumental methods of analysis. Each one has a worked solution and a mark scheme showing where the marks go.