Graphic method for the determination of titration end-points.
An extension of Gran's method for the détermination of equivalence points in potentiometric acid-base titrations is presented. Equations are derived assuming that the stability constants of the reactions are known. The equations make it possible to locate the equivalence point with fair accuracy when acids with stability constants ranging from K(H)(HA) ~ 10(7) to K(H)(HA) ~ 10(10) are titrated. The limit of K(H)(HA) above which Gran's equations do not yield satisfactory results is about 10(7). Conditional constants and a-coefficients are used to extend the method to apply to more complex systems, where more than one species reacts with the titrant.
Ingman
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F
Department of Analytical and Inorganic Chemistry, Abo Akademi, Abo, Finland.
Still
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E