What is the difference between a strong acid and a weak acid titration?

A strong acid titration involves a strong acid reacting completely with a base, while a weak acid titration partially reacts.

In a strong acid titration, the acid, such as hydrochloric acid or sulfuric acid, fully dissociates into its ions in water. This means that every molecule of the acid breaks apart and reacts with the base, typically a strong base like sodium hydroxide. The reaction goes to completion, meaning all the acid and base react until one is used up, resulting in a neutral solution. The pH at the equivalence point, where all the acid and base have reacted, is 7, indicating a neutral solution. The titration curve for a strong acid titration shows a sharp change in pH at the equivalence point.

On the other hand, a weak acid titration involves a weak acid, such as acetic acid or phosphoric acid, which only partially dissociates in water. Not all molecules of the acid break apart, so not all of them react with the base. The reaction does not go to completion, and there is always some unreacted acid left in the solution. The pH at the equivalence point is greater than 7, indicating a slightly basic solution. The titration curve for a weak acid titration shows a more gradual change in pH at the equivalence point.

The difference between these two types of titrations is important in determining the end point of the titration, which is the point at which the indicator changes colour. In a strong acid titration, the end point and the equivalence point are the same, but in a weak acid titration, the end point may occur before the equivalence point due to the presence of unreacted acid. This can lead to inaccuracies in the determination of the concentration of the acid or base.