The Debye-HOckel Theory

Table II. Standard Potential of the Cell, Zn ZnS04l PbS04(s) Pb(Hg) at 25° as Computed by the Gronwall, LaMer and Sandved Extension of the Debye-HOckel Theory...

The Debye length is defined in mathematical terms In appendix A.3.3 which describes the Debye-HOckel theory. Some orders of magnitude are given later in the text. 

Assuming that the cation and anion activity coefficients are equal, which is in the case particular in the context of the Debye-HOckel theory, simplifies the calculation yet without making the reasoning any less general. 

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