ABSTRACT
The term acid is in everyday use. We associate the word particularly with food. For example, we say that lemon juice and vinegar are acidic. And if we recall school chemistry, we probably know that the terms ‘basic’ and alkali are somehow associated with the concept of acidity. But what do we mean by acidity? It would be convenient at this point to offer short, simple definitions of the terms. However, the fact is that the gradual evolution of the concepts of acidity has led to definitions that are hard to appreciate. A better approach is to introduce you to the development of thought about acidity, before seeing what useful definitions can be applied.
