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Die Bestimmung thermodynamischer Aciditätskonstanten
Author(s) -
Bates Roger G.,
Schwarzenbach G.
Publication year - 1954
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19540370415
Subject(s) - chemistry , extrapolation , ionic strength , dissociation constant , ion , ionic bonding , yield (engineering) , inorganic chemistry , cationic polymerization , thermodynamics , analytical chemistry (journal) , aqueous solution , chromatography , organic chemistry , physics , receptor , mathematics , mathematical analysis , biochemistry
Abstract The determination of thermodynamic acidity constants (dissociation constants) requires the elimination of all salt effects by an extrapolation to zero ionic strength. Laborious curvefitting may be necessary, and the results may be of low accuracy unless an extensive series of data is available. It is shown that the extrapolation can be reduced to a simple extension of a straight line of small slope when suitable experimental data are combined in the proper way. Measurements of spectral absorption and of e.m.f., taken together, will yield thermodynamic acidity constants not obtainable by either method alone. The procedures are illustrated by the determination of the acidity constants for three uncharged acids (p‐nitrophenol, 2,4‐dinitrophenol and 4‐chloro‐2,6‐dinitrophenol) and for three cationic acids (m‐nitroanilinium‐ion, p‐chloranilinium‐ion, and N,N‐diethyl‐p‐toluidinium‐ion).