Partial molar quantities in an ideal-dilute solution

7 Partial molar quantities in an ideal-dilute solution 

Next consider a solute, B, of a binary ideal-dilute solution. The solute obeys Henry s law, and its chemical potential is given by /Tb = 3 + 7 In xb (Eq- 9.4.24) where 3 

The term -(9/r j g/9r) represents the partial molar entropy 5 g of B in the fictitious reference state of unit solute mole fraction. Thus, we can write Eq. 9.4.36 in the form 

This equation shows that the partial molar entropy varies with composition and goes to -1-00 in the limit of infinite dilution. From the expressions of Eqs. 9.4.27 and 9.4.28, we can derive similar expressions for 5b in terms of the solute reference states on a concentration or molality basis. 

When the pressure is equal to the standard pressure the quantities and are the same as the standard values V, Uq, and C°.  

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