Demostração da determinação do ponto final numa titulação potenciométrica com ajuda das funções Gran

Abstract

Potentiometric titration is an instrumental method that is widely used in the determination of concentration of the various chemical species present in acid-base, precipitation, complexation and oxidation-reduction reactions, using a simple apparatus consisting of a potentiometer, an indicator electrode, a reference electrode and also a calibrated one, a closed cup for the solution and a stirring system for the solution under analysis. Instrument readings can be taken in units of pH or E potential (mV) as the titration progresses. Detecting the equivalence point (equivalence volume) is the main objective of the titration. This point is revealed by an abrupt change in the potential in a certain region of the potential graph, (E, mV) of the solution versus the Volume (v, ml) of the titrant. There are different techniques for locating equivalence points in potentiometric titrations, namely: a) Normal tangent method b) First derivative method c) Second derivative method d)m Method of Gran functions