Acids, Bases, pH, Indicators and Buffers

This topic is mostly about equilibria so it is important for students to understand that concept first. Before tackling this topic make sure you :

understand dynamic equilibria
can write and manipulate equilibrium expressions for a range of reactions.
can estimate the pH value of a solution using universal indicator
know the pH values associated with : strong acids, weak acids, neutral solutions, weak alkalis and strong alkalis.

When an acid molecule ionises completely when in solution in water, it is regarded as a strong acid. It is said to dissociate completely.

If we consider this ionisation to be an equilibrium - it would lie completely to the right.

The equilibrium constant (K_c) would be a very large value and not really useful.

When calculating pH values for strong acids we assume that the concentration of H⁺ions is equal to to the concentration of the acid.

Matt from chemistrystudent.com does a brilliant job of explaining buffer solutions here...