Effect of applied pressure on solubility

The discussion in the preceding paragraph may now be used to examine the effect of pressure on solubility that is to say on conditions away from the eutectic point. We now have crystals of 2 in equilibrium with a solution consisting of 1 and 2. We need now only consider the second equation of (22.24). Under isothermal conditions 

As before the denominator must be positive because of the stability condition so that the sign of this expression is that of 

The behaviour of strong electrolyte solutions is of particular interest in this connection. The expansion on fusion is opposed by the contraction on mixing and under certain circumstances these may cancel exactly so that 

An example of this behaviour has been given already in fig. 22.7, where there is a temperature at which the solubility is independent of the pressure. 

In the last chapter we considered one particular type of freezing point diagram, namely that exhibiting a eutectic. We now study other kinds of freezing point diagram. 

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