Theory of Electrolytic iJissociution. -1 < 



solutions cryoscopically examined by Loomis. II' one were 

 therefore to take the attitude of Wnetham, there would '<«• 

 no unobjectionable experimental evidence whatever on hand ;it 

 present upon which to base the claim that freezing-points and 

 molecular conductivity arc related, a- held by Arrhenius 



It may be asserted that all data of freezing-points and 

 boiling-points of solutions on the one hand, and of molecular 

 conductivities on the other, when carefully scrutinized, -how 

 that there i> no such relation between them a- the theory of 

 electrolytic dissociation requires. While here and there 

 isolated values of the degree of electrolytic dissociation, as 

 calculated from molecular conductivities OH the one hand and 

 molecular-weight determinations on the other, agree approxi- 

 mately, this agreement Is generally not within the limits <>t 

 experimental error, and hold- only for a ver} limited range 

 of concentration. 



In order to show that I was fully cognizant of the fact 



that the theories of van't Hott' and Arrhenius hold strictly 

 only for infinitely dilute solutions, and that my argument 

 against these hypotheses was based upon the general trend 



of the results, as varying from what would be expected were 

 moderately concentrated solutions to behave like compi 

 gases, I should like to quote the following paragraph from 

 my paper above cited : — 



■* I am well aware that ihe gas equation i> supposed t<» 

 hold strictly only for infinitely dilute solutions, just as it 

 holds only for ideal eji>es ; and that the solutions with which 

 Dieterici worked varied between 0*1 and L"0 normal, and 

 that those used in experiments detailed above frequently were 

 much stronger than normal. That a normal solution i- 

 nevertheless for many of the practical purposes of life a 

 rather dilute solution will hardly he disputed. No one ex- 

 pects the gas equation to hold strictly for a normal solution 

 or even \'ov one considerably more dilute: hur what one has 

 a. right to expect from the modern theory of solutions i>. that 

 with increasing concentration a solution should behave at 

 least qualitatively as a gas does with increase of pressure. 

 And this requirement i> clearly not met, since while all gases 

 behave alike under increase of pressure (so that van der 

 Waals has been able to express their behaviour by mean- k)( 

 his well-known equation) solutions as has been shown, often 

 behave in a manner opposite to thai of oases, and this, too. 

 frequently in solutions that cannot be termed concentrated. 

 This demonstrates, then, that the van't Hoti' law is at best 

 only approximate and must be applied with groat care. 

 As Dieterici well says : — 



wu ' Raoult hat seine Geset/.e der Dampfspannungs- und 



