Solutions of Gases in Liquids at High Pressures

Dilute Solutions of Gases in Liquids at High Pressures 

In the previous sections, we emphasized that at constant temperature, the liquid-phase activity coefficient is a function of both pressure and composition. Therefore, any thermodynamic treatment of gas solubility in liquids must consider the question of how the activity coefficient of the gaseous solute in the liquid phase varies with pressure and with composition under isothermal conditions. 

The simplest assumption one can make for a dilute solution at low pressure is to assert that the activity coefficient of the solute is a constant, independent of both pressure and composition. This assumption leads directly to Henry s law for the solute (component 2), we obtain 

For a dilute solution at high pressure, the variation of activity coefficient with pressure cannot be neglected. But when x2 is small, it is often a good approximation to assume, as above, that the activity coefficient is not significantly affected by composition. If we also assume that v2 the partial molar volume of the solute, is independent of both pressure and composition 

Solubility of nitrogen in water at high pressures. Fugacity is in atmospheres. 

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V. Dilute Solutions of Gases in Liquids at High Pressures. 166... 

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