CHEMICAL THEORY OF SOLUTIONS. PAET I. 



17 



with the axis S3 ©2« Hence if 

 there is much of ©3 in the original 

 solution the curve will have a form 

 like ©1 C'Bo. On the contrary, 

 when there is but little of @3 the 

 curve will have a form like ©j^So- 



If a = 0, 



and 



da _ _-, 



so that the curve coincides wdth the axis ©2 ©i- 

 The equation (7) can be written 



dC, ^ __C,{{P,-F,)C\ + {P,-P,){1-C,-C,)] 



dC\ C,{(P,-P^ c^çp.-PSiji-c,~c^y 



which can be readily transformed into 

 On integration we get 



c'P^.-p. a^.-p. c/.-p. == e.A-^'a g/3-A 6 A-A.... 



.(8) 



where (5i, ©2, and ©3 are the initial molar fractions of the com- 

 ponents. This is the equation of the curve of isothermal dis- 

 tillation. 



The composition and the quantity of the residue during the 

 process of isothermal distillation of a ternary mixture can be 

 calculated in exactly the same manner as in the case of a binary 

 system. AVe have 



di}, : dn. : dn^ = (7/ : C/ : (7/ 



