electrode that records the change of the potential as a function of the amount (usually the volume) of the added titrant of exactly known concentration. Potentiometric titrations are especially versatile because indicator electrodes suitable for the study of almost every chemical reaction used in titrimetry are now available. This technique is also frequently used in the study of operational conditions of visual titrimetric indicators proposed for general use in chemical analysis, as well as in the study of numerous reactions, such as protonation and complexation, which find their application not particularly in analytical measurements. The course of the potentiometric titration curve provides information not only about the titration end point position, but also the position and shape of the curve may provide data about the processes accompanying the titration reaction. Another advantage is that the necessary apparatus is generally not expensive, reliable and readily available in the laboratories.