The empirical partial pressure curves of binary solutions

The empirical partial pressure curves of binary solutions 

X This difficulty is the same as the one already mentioned in 7 1, namely, knowing the chemical potential as a function of the composition of the solution. 

The functional relationships (7 25) are known as RaouU s law. Mixtures which obey the law over the whole range of composition are the exception rather than the rule, but an approximation to the ideal behaviour is usually found whenever the components are closely similar in molecular structure. Much more frequently the observed partial pressures are of the types shown in Figs. 26 and 27, which 

Another important feature of these curves, closely connected thermodynamically with that which has just been mentioned, is 

In brief the empirical study of the vapour-pressure curves of binary liquid mixtures shows that at the one side of the diagram we have 

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