Setchenow constant

Ohtaki H, Radnai T (1993) Structure and dynamics of hydrated ions. Chem Rev 93 1157-1204 Parfenyuk VI (2002) Surface potential at the gas-aqueous solution interface. Coll J 64 588-595 Pawilkowski EM, Prausnitz JM (1983) Estimation of Setchenow constants for nonpolar gases in common salts at moderate temperatures. Ind Eng Chem Fund 22 86-90 Pitzer KS (1979) Theory ion interaction approach. In Pytkovicz RM (ed) Activity coefficients in electrolyte solutions, Vol. 1. CRC Press, Boca Raton, (Chap. 7)... 

In addition, the high concentrations of ions in solutions of high ionic strength such as sea salt particles (especially near their deliquescence point) can alter gas solubility. In this case, the Henry s law constants must be modified using Setchenow coefficients to take this effect into account (e.g., Kolb et al., 1997). 

The effect of electrolytes on the solubility of nonelectrolytes is generally to deaease the solubility of the nonelectrolyte (salting-out). Taking O2 as the nonelectrolyte and the relevant solubility data from the text, obtain Setchenow s constant for HCl and Ac2[Pg.217]

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. 

Plyasunov et al. (1988) used a combination of the Debye-Hiickel and Setchenow approximations together with literature data for the activity coefficients of NaOH solutions to determine the dissociation constant of NaOH(aq) from 0 to 350 °C. The combination of the approximations was used such that the calculated activity coefficients best matched the literature values whilst obtaining values for the dissociation constant at each temperature. In general, the values of the dissociation constant (obtained from the reverse of reaction (2.7) (M = Na, p=l, q=i)) were found to increase with increasing temperature they also increased slightly below 50 °C. However, when combined with the dissociation constant of water (i.e. for reaction (2.5)), the stability constants increase with increasing temperature across the whole temperature range (see Table 6.5). The data obtained by Plyasunov et al. (1988) are more positive than those of other studies at low temperature but become more consistent with other data at, and above, a temperature of 150 °C. There is no apparent reason to reject any of the data, and so all are retained in the present review. 

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