Preferred Label : Debye–Hückel equation;
IUPAC definition : The chemical potential or activity of ions cannot be determined on a purely thermodynamic
basis. This is due to the fact that the effects of an ion cannot be separated from
the effects of the accompanying counter-ion, or in other terms, the electrochemical
potential of the ion cannot be separated into the chemical and the electrical component.
Such a separation must necessarily be based on a non-thermodynamic convention. The
present convention is based on the assumption that the molal activity coefficient
of the chloride ion in dilute aqueous solutions (I 0.10 mol kg-1) can be estimated
by means of the Debye–Hückel equation: \[-\log _{10}γ _{{B}} \frac{z_{{B}} {2}\ A\
\sqrt{I}}{1 \mathring{a}\ B\ \sqrt{I}}\] where I is ionic strength, z is the charge
number of the ion, å is ion size parameter and A and B are temperature-dependent constants.
According to the Bates–Guggenheim convention åB is taken to be 1.5 x sqrt(mol kg-1)
at all temperatures and for all compositions of the solutions.;
The chemical potential or activity of ions cannot be determined on a purely thermodynamic
basis. This is due to the fact that the effects of an ion cannot be separated from
the effects of the accompanying counter-ion, or in other terms, the electrochemical
potential of the ion cannot be separated into the chemical and the electrical component.
Such a separation must necessarily be based on a non-thermodynamic convention. The
present convention is based on the assumption that the molal activity coefficient
of the chloride ion in dilute aqueous solutions (I 0.10 mol kg-1) can be estimated
by means of the Debye–Hückel equation: \[-\log _{10}γ _{{B}} \frac{z_{{B}} {2}\ A\
\sqrt{I}}{1 \mathring{a}\ B\ \sqrt{I}}\] where I is ionic strength, z is the charge
number of the ion, å is ion size parameter and A and B are temperature-dependent constants.
According to the Bates–Guggenheim convention åB is taken to be 1.5 x sqrt(mol kg-1)
at all temperatures and for all compositions of the solutions.
