Survey of Experimental Observations

In this section, as in most of the remaining sections of this chapter, we confine ourselves to the discussion of aqueous solutions of the simplest solutes, e.g., inert gases or simple hydrocarbons. 

Eley (1939) was the first to investigate systematically the anomalous behavior of aqueous solutions of inert gases. We shall describe in Section 7.3 his contribution to the theory of these systems. Here, we survey the experimental facts. Only representative examples are given to illustrate the outstanding behavior of aqueous solutions. [A review article concerned mainly with the experimental facts has been published by Battino and Clever (1966). Other reviews are by Ben-Naim (1972e) and Franks (1973a).] 

The solubility of a gas will always be given in terms of the Ostwald absorption coefficient. This is defined as follows Let be the volume of the gas (at a given T and P) dissolved in a given volume of liquid (at the same T and P). The Ostwald absorption coefficient is defined by 

This is a practical definition in terms of directly measurable quantities. A more useful form, equivalent to (7.11), is obtained as follows. Let Qs and Qs be the molar concentration of the solute S in the liquid and gaseous phases at equilibrium, respectively. Then, since the number of moles of solute in the liquid originated from the gaseous phase, we have the equality 

There exists a variety of other units by which solubility data may be reported these and the interconversion formulas are discussed in the literature (Hildebrand and Scott, 1950 Friend and Adler, 1957 Himmel-blau, 1959 and Battino and Clever, 1966). In this chapter, we adhere to the application of the Ostwald absorption coefficient as a measure of the solubility. 

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The theory for predicting polymer-polymer miscibility is not well developed at this time, but a brief and incomplete survey of experimental observations on a variety of systems suggests that many miscible systems exist (28-51). The existence of miscible-phase behavior depends on the chemical structures of the blend components (21,44,46), including co-... 

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