462 Prof. F. P. Worley on the Decline of the 



of the electrolyte at different dilutions and different degrees 

 o£ ionic dissociation. The velocity coefficients so calculated 

 increase as dilution is increased but at a lower rate than 

 the assumed degree of ionization of the electrolyte. In 

 the experiment cited (/. c. p. 355) the value of the velocity 

 coefficient, expressing the molecular activity of sodium 

 ethylate, increases from 0*075 to 0*0998, when the dilution 

 is changed from one molecular proportion in two litres to 

 one in forty litres, the corresponding change in ionic dis- 

 sociation being from 0*148 to 0*605. It is clear that the 

 velocity of interaction cannot be correlated with the concen- 

 tration of the assumed ethylate ion alone. The assumption 

 has therefore been made that it is dependent both on the 

 ethylate ions and also on the non-ionized sodium ethylate 

 molecule. By solving a series of simultaneous equations, 

 values of Kj and K m are obtained expressing the activity of 

 the ion and of the molecule respectively. In the experiment 

 cited the values of K; and K m have a remarkable degree of 

 constancy but more important is the fact that the value 

 of K; for the ethylate ion, arrived at from experiments with 

 sodium ethylate and potassium ethylate, is practically the 

 same for both salts, though the values of ~K m for the mole- 

 cules are different. In the case of the phenolates of lithium, 

 sodium and potassium, the values of K t - for the phenolate 

 ion are nearly identical, while those of K TO for the molecules 

 vary considerably. It is impossible at present to discuss 

 other possible explanations of this numerical agreement than 

 the one advanced. Although Acree has for some time 

 advanced the view that in hydrolytic change undissociated 

 molecules may be partly concerned, he is guarded in his 

 acceptance of the results as a proof of the truth of his hypo- 

 thesis and it must always be borne in mind that there may 

 be various possible explanations for such numerical agreement. 

 However, it is not the object of this paper to discuss the 

 methods by which Bredig and Snethlage and Acree have 

 arrived at their conclusion but rather to examine some of 

 the consequences of this remarkable change of attitude on 

 the part of supporters of the doctrine of ionic dissociation. 



In the first place, it is not necessary to confine our atten- 

 tion to non-aqueous solutions as the above investigators have 

 done. Acree's method especially is very widely applicable, 

 as the molecular chemical activity of an electrolyte rarely 

 changes in exactly the same way on change of concentration 

 as its degree of ionic " dissociation." This important fact has 

 been much neglected by supporters of the ionic dissociation 



