Chemistry (5070) Experimental techniques and chemical analysis Learn key ideas from 12.5 Identification of ions and gases, then practise 15 questions across Easy, Medium, and Advanced levels. Key TheoryLearn FirstLoading… Key WordsKnow TheseLoading… Common MistakesAvoid TheseLoading… StrategyApply ThisLoading… Practice 1EasyLoading… Practice 2MediumLoading… Practice 3AdvancedLoading…