THE THEORY OE ELECTROLYTIC DISSOCIATION AS 

 VIEWED IN THE LIGHT OF FACTS RECENTLY 



ASCERTAINED. 



Introduction. 



The theory of electrolytic dissociation, as advanced by Arr- 

 henius 1 in 1887, is based primarily upon the facts that the 

 molecular conductivity of solutions increases with the dilution ; 

 that substances which when dissolved conduct electricity also 

 have abnormally low molecular weights in such solutions when 

 tested by osmotic or freezing- or boiling-point methods; and 

 that the so-called degree of dissociation may be calculated from 

 the electrical conductivity, or the results of the molecular weight 

 determinations. In his original article Arrhenius states that 

 the phenomena of electrolysis when viewed from the standpoint 

 of thermodynamics, require the assumption of the presence of 

 free ions, as was pointed out by Clausius, and that the heats 

 of neutralization of acids and bases in dilute solutions and the 

 various physical properties of salt solutions, which are well 

 known to be additive in character, support the electrolytic dis- 

 sociation hypothesis. The effect which the publication of that 

 memorable article of Arrhenius had, need not be dwelt upon at 

 length here. Suffice it to recall that its author sought to save 

 van't Hoff's theory of solutions from having but a limited ap- 

 plication, and at the same time to bring into correlation facts 

 that had hitherto been entirely isolated. Chemists and phys- 

 icists alike were astonished by the audacity of the assumption 



*Zeit. Phys. Chem. 1, 629 (1887). 



