Why a test must be unique
Why a test must be unique
A test identifies an ion only when its result is not shared by another ion. A white precipitate on its own is not enough evidence because several ions can produce a white precipitate.
Step-by-step lessons on Edexcel GCSE Chemistry 10.1.1 Principles of ion tests and flame tests. Each one builds up to exam-style questions. Nail the core quantitative topics — moles, balancing equations and calculations — early on, since they underpin higher-tier questions across every paper and topic.