fxdmd-T:) £or ^^^j** po 



is 





414 Dr. Meyer Wilderman on the Connexion between 



CC" ) T" — T ' 

 I does not change with temperature, that 77T- = m frrj for 



fC // ) CT" T-'V 



non-electrolvtes (III.), and ) ( , x =7?n n^w^ £or electro_ 



lytes (III/). For the solubility curve we shall have for the 

 same T //v and any other temperature between T /y/ and T„ 



c 



(C //7 ) 



and lg (c£) = 2x^26 (t - t 1 ;) for eiectrol J tes ff-0- 



Assuming that i does not change for concentrated or satu- 

 rated solutions, and that q does not change with temperature, 

 we get 



Csol. _-<l (1 J\ T"-T</ 



(<J")b.p. ' " 2x'2-Z(m\T T„/J g T //7 -T " 



for non-electrolytes, and 



18 (C")b,p. 2x2-302dx« /// It T,J 8 (T (// -T,0i 



for electrolytes (B). 



This equation gives the connexion between solubility at any 

 temperature T, the boiling -point at any temperature T /r , the 

 latent heat of solution q. and the temperature T //y , which is the 

 point where the solubility and the boiling-point curves cut each 

 other, the concentration at T yyy remaining unknown. 



In the case of non-electrolytes, since the molecular rise of 

 the boiling-point is the same for all substances when the 



same solvent is used, lg (C")— lg(T"-T ')=lg ~ for 



water, i. e. we are able to calculate the whole solubility 

 curve, if T /yy and q are known, using the equation 



In case of electrolytes the additional knowledge of van't 

 Hoff's i is necessary. 



In Table IV. the solubilities are calculated from boiling- 

 points for boric acid and C10 3 K : in the first case Iff ^— ^ 



o"2 



instead of the observed lg(C")-lg (T"-T ') is used. Con- 

 sidering that the values of q and / were assumed to be 

 independent of temperature, and that the solubilities at 

 higher temperatures are not very easily correctly determined, 



