Graphic determination of equivalence volumes in potentiometric titrations of mixtures of weak acids-II Titration of a dibasic acid and determination of its two acid species H(2)A and HA(-).
The method given in part I is used to determine the mixed stability constants of a dibasic acid. Values of log K(H)(HA(2)) = 2.878 and log K(H)(HA(2)) = 4.011 for tartaric acid and 4.077 and 5.335 for succinic acid at mum = 0.1 and T = 25 degrees have been obtained. The method is also applied to titrations of these acids, the error obtained being about 0.5 %, and to titrate a mixture of tartaric acid and potassium hydrogen tartrate with an error of 0.7-1.6%
Ivaska
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Department of Analytical Chemistry, Abo Akademi, Abo 50, Finland.