Solubility of volatile weak electrolytes

On the Solubility of Volatile Weak Electrolytes in Aqueous Solutions... 

Maurer G. On the solubility of volatile weak electrolytes in aqueous solutions. ACS Symp Ser 1980 133 139-172. 

From G. Maurer, "On the Solubility of Volatile Weak Electrolytes In Aqueous Solutions", Thermodynamics of Aqueous Syatema with Industrial... 

Maurer, G., "On the Solubility of Volatile Weak Electrolytes in Aqueous Solutions", Thermodynamics of Aqueous Systems with Industrial Applications. S.A. Newman, ed., ACS Symposium Series 133, Washington D.C.. ppl39-172 (1980)... 

SOLUBILITY OF A WEAK ELECTROLYTE IN SALT SOLUTIONS. Calculation of the solubility of a volatile strong electrolyte, such as HCl, in aqueous salt solutions is straightforward. However, solubilities of weak electrolytes are more difficult to model accurately, since the dissolved speciation must frequently be determined in addition to the activity of the component of interest. Thus, in the case of NH3, the relevant ionic interactions involving NH4 and OH" must be known in addition to parameters for the interaction of dissolved salts with the neutral NH3 molecule. See, for example, the work of Maeda et al. (47) on the dissociation of NH3 in LiCl solutions. 

This work and others (5, 51) have shown how the Pitzer model, together with appropriate Henry s law constants, can be used to calculate the solubility of volatile strong electrolytes in multicomponent solutions. The treatment of NH3 summarized above shows that Pitzer formalism can also be used to describe the solubility of weak and non-electrolytes. We have noted how, for low concentrations of NH3, the Pitzer equations reduce to a series of binary interaction terms similar in form to those of the well known Setchenow equations. However, the thermodynamically based approach constitutes a significant improvement over the use of purely empirical equations to predict individual thermodynamic properties because it is equally applicable to both electrolytes and uncharged species, and provides a unified description of a number of important solution properties. 

Because of its wide range of applications, the thermodynamic properties of electrolytes have been the subject of much interest even in recent literature [1, 2, 3]. Certainly, among physical chemists, the most popular expressions have been the Debye-Hiickel limiting laws (DHLL), and expressions derived therefrom [4]. Among others, geochemists, have used extensively Pitzer s modifications of DHLL to describe departures from ideality in concentrated ionic mixtures (typically up to 6 mol/kg [5], and up to 10-20 mol/kg, between 0 and 170°C, for solutions of volatile weak electrolytes [6]). Also solubilities of minerals in natural waters can be predicted accurately [7]. 

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