A neutral solution has [ or . (Most of the hydrogen ions actually exist in aqueous solution as hydronium ions ). Around an equivalence point, where stoichiometric neutralization is approached, the versus volume curves increase steeply. The inflection point of the curve marks the precise location of the equivalence point. The progress of the titration automatically slows down in the Demonstration so that volume can be determined more accurately.

A weak acid exhibits a relatively flat curve to the left of the equivalence point. This provides the basis for buffer solutions, which maintain a nearly constant over a range of concentrations. This behavior can be approximated by the Henderson-Hasselbalch equation . Thus a weak acid is most effective as a buffer around .

Before electronic meters were developed, indicators were commonly used to follow the progress of neutralization. Each indicator undergoes a characteristic color change around a specific value. Five common acid-base indicators are available in the Demonstration.