What principle does volumetric analysis rely on?

Volumetric analysis is a quantitative analytical method that focuses on measuring the volume of a solution needed to react with a sample to determine its concentration. This technique relies on the precise measurement of liquid volumes to achieve accurate results. By using a reagent of known concentration, the amount of the reagent required to completely react with the analyte is measured. This process is pivotal in titrations, where the endpoint is indicated by a change in color or some other measurable signal, corresponding to the completion of the reaction.

Measuring changes in volume is fundamental to the principle of volumetric analysis because it allows chemists to calculate the unknown concentration of a solution based on the volume of titrant used. By applying stoichiometric relationships derived from balanced chemical equations, the actual concentration of the unknown solution can be inferred from the volume of titrant that reacted.

On the other hand, counting particles, measuring the diameter of particles, or measuring weight doesn't directly pertain to the core principle of volumetric analysis, as those methods primarily involve different types of analyses such as gravimetric or particle size analysis. These do not focus specifically on the volume of solutions in the same way that volumetric analysis does.