You’ll find absolutely everything you need to know about acids, bases, buffers and pH – from the basics to complex calculation explanations and walk-throughs with plenty of exam style question practice along the way.

How do you define an acid or a base?

At GCSE we defined acids as substances that ionised in water to give hydrogen ions and bases ionised in water to give hydroxide ions, but this definition limits us to thinking about acids and bases only in the context of aqueous solutions …

What are conjugate acid-base pairs?

Many acid-base reactions are equilibrium reactions. When an acid donates a proton, the resulting anion can behave as a base …

What is the ionic product of water?

We can write an equilibrium expression for the self-ionisation of water and the equilibrium constant is called the ‘ionic product of water’ …

Strong acids, weak acids and pH

Find out how to calculate the pH of a strong and weak acid …

How do you calculate the pH of a base?

Step-by-step methods for calculating the pH of strong and weak bases, along with a few practice Q&A …

Everything buffers

From explaining exactly what a buffer does to calculating the pH of a buffer, including the derivation of the Henderson-Hasselbalch equation (and lots of practice Q&A) …

How do you explain the shape of a titration curve?

Strong acid / strong base, strong acid / weak base, weak acid / strong base – and an explanation of why the equivalence point doesn’t necessarily correspond with products at pH7 …