4.2 understand how the pH scale, from 0-14, can be used to classify solutions as strongly acidic, weakly acidic, neutral, weakly alkaline or strongly alkaline

4.2 • 0-6: acids (less is stronger)

      • 7: neutral

      •8-14: alkaline (more is stronger)

      •strong acid: cars battery / nitric acid

      •weak acid: vinegar / citric acid

      •strong alkaline: drain cleaner / dilute sodium hydroxide 

      •weak alkaline: washing-up liquid / dilute ammonia solution