34 AET. 10. — K. IK EDA : STUDIES ON THE 



between a solid component or a solid compound and an ideal 

 solid solution may be treated just in the same manner as in the 

 foregoing section. 



(«) Isothermal Relations. 



The relation between the compositions of an ideal liquid 

 and an ideal solid solution at a constant temperature can be 

 found in the following manner. Let fi^ and /z^" be the molecular 

 chemical potential of the first component in the liquid and the 

 solid phase respectively. Then we have by equation (3) 



/A = z, + FiTlnC, 

 and li," = z," + RTlnC\" 



where z^" and d" denote the corresponding quantities for the 

 solid solution, as z^ and CA for the liquid phase. In the case 

 of equilibrium 



Ih = y■^" 



hence 



hi-^^ =iî ^ (20) 



6V' BT ^ ^ 



The supposition that z^" as well as z^ is independent of pressure 

 may be looked upon as a close approximation as long as the 

 variation of pressure is not very considerable. Under this as- 

 sumption we have 



^;^=r,= const (21) 



for a constant temperature. Similarly 



