The terms ‘strong’ and ’weak’ in the context of acids and bases are used to describe the degree of ionisation of the acid or alkali. However, these terms are often confused with ‘concentrated’ and ‘dilute’ which have a profoundly different meaning. The acid dissociation constant, Ka, expresses the degree of ionisation of an acid and can give a rank order of strengths of various acids according to the Ka or pKa values.
After working through this topic you will be able to:
- Explain what is meant by strong, weak and the acid dissociation constant;
- Consider students difficulties with the concepts of ‘strong’ and ‘weak’ and access a range of resources to support the learning and teaching of this topic;
- Use effective strategies to support students’ understanding of Ka, pKa and the link with pH.