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[This cc provides a reminder that students appreciate real contexts for chemistry; it shows importance of this topic to everyday life, as well as a fun introduction to amuse]

The reaction of an acid and a base is a neutralisation reaction. Neutralisation is a very useful reaction with many and varied examples around us in daily life. For example, toothpaste is an alkali in order to neutralise acids in the mouth that would otherwise damage our teeth. A neutralisation reaction changes the pH of both the acid and base towards pH 7. Many more everyday life situations exemplifying neutralisation will be considered at the end of this topic.

In order to understand what's happening in a neutralisation reaction, it's crucial to consider the ions that are in both the solutions of the alkali and the acid. Consider the following reaction:

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[critial to get to grips with neutralisation at particle level, hence use of animation]

In summary, when H⁺ ions from an acid react with OH^– ions from an alkali, water is formed in a neutralisation reaction and may be viewed simply as:

H⁺(aq) + OH^–(aq) _↓ H₂O(l)

This simplified equation, showing only the reacting species, is an ionic equation. Further consideration is given to ionic equations in the Exploring Understanding section of this topic. You can also find out more by subscribing to the Redox course.