ISSN:
1572-8927
Schlagwort(e):
Electrochemical thermodynamics
;
standard emfs
;
standard potentials
;
activity coefficients
;
nonaqueous solvents
;
mixed solvents
;
aqueous-organic solvent mixtures
;
hydration numbers
;
amalgam electrode
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract The electromotive force of the amalgam cell {NaxHg1-x‖NaCl(m)‖AgCl‖Ag} has been measured at 25°C as a function of the mole fraction x of Na in amalgams and of the molality m of NaCl in (ethylene glycol + water), (acetonitrile + water), and (1,4-dioxane + water) mixed solvents, containing up to 0.8 mass fraction of the organic component, with relative permittivities ε ≥ 27. The relevant standard molal electromotive forces $$E_{\text{m}}^ \circ $$ have been determined, together with the mean molal activity coefficient γ± of NaCl as a function of its molality. In the case of (ethylene glycol + water) mixtures, a linear dependence of $$E_{\text{m}}^ \circ $$ on the mass fraction of ethylene glycol is observed, which is quite unusual, The Debye-Hückel equation is applicable successfully over the whole range of molalities explored, which extends to the vicinity of the solubility limit of NaCl in each solvent. The dependence of the standard emf on the logarithm of the volume fraction of water in the aqueous-organic solvent mixtures have been analyzed in terms of Feakins and French's theory, leading to a primary hydration number 7.2 for NaCl, in good agreement with previous results employing different methods.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1022981107236
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