ISSN:
1572-8927
Keywords:
Activity coefficients
;
aqueous solution
;
emf
;
membrane electrodes
;
barium hexacyanoferrate (III)
;
calcium hexacyanoferrate (III)
;
magnesium hexacyanoferrate (III)
;
strontium hexacyanoferrate (III)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The relative mean activity coefficients of the M3[Fe(CN)6]2 salts, M=Mg, Ca, Sr, Ba, are measured down to about 5×10−6 mol-kg−1 using the liquid membrane cell method. In the dilute region these salts display negative instead of positive deviations from the limiting law, contrary to Debye-Hückel's theory predictions. An indirect method based on auxiliary emf measurements in MCl2, K3Fe(CN)6 and KCl, rather than a theory-assisted direct extrapolation to zero of the relative activity coefficients, is used to identify the actual values of the activity coefficients. The data are compared with Mayer's theory, ion-pair theory and numerical integration of the Poisson-Boltzmann equation. Best-fit coefficients of Pitzer's equation which meet the activity coefficients of the M3[Fe(CN)6]2 salts to be reproduced, are reported.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00972759
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