定電位滴定による解離定数の決定

抄録

The present paper deals with the determination of dissociation constants in terms of potentiostatic titration at constant ionic strength. This method is an improved Kankare's ones, and is simpler than the Kankare's, since the degree of dissociation is needless for calculation of dissociation constants. If hydrogen ion concentration [H] of an acid solution is known, the following equation is applicable for the determination of cumulative dissociation constant of a polybasic acid HnA:
E KJBI-F[011i]. [H]i-t. fl=[H][OH]where Ci:
concentration of the acid solution, : cumulative dissociation constant at i-th dissociation. When the above simultaneous equation is solved for at least n pieces of Ci, fit (i=1, 2, n) can be obtained. If Kankare's data on acetic acid (monobasic acid) and citric acid (tribasic acid) were applied to the above equation, the obtained dissociation constants were more precise than the Kankare's results, especially in the case of citric acid. Further, the dissociation constants of tartaric acid (dibasic acid) were determined to be M=2.8390.011 and 02=6.771 0.013 at 25° C in O.1 moll KCl solution.