456 STUDIES IN GENERAL PHYSIOLOGY 
3. Can we now say that in these experiments we are deal- 
ing only with the effects of the hydrogen ions? In order 
to decide this question, we must see which fraction of the 
molecules of acid is dissociated at the dilution employed. 
If we designate that fraction of the molecules which are 
dissociated by a, then, as is well known, a = , where 
co 
#, represents the molecular conductivity of the electrolyte at 
the dilution v, wg the molecular conductivity at infinite 
dilution. 
* According to Ostwald,’ the speed of migration of the H 
ions at 25° — 325, that of the Clions =70.2. According to 
Kohlrausch’s law », is for HCl therefore=395. In the 
same way we find for HNO;, ,. =390. According to 
Kohlrausch, the speed of migration of H ions at 18° = 290. 
That of SO, can be determined indirectly as about 132.? 
Mg is therefore at this temperature 712 for H,SO,. 
When V= 200, », for HC1=377, for HNO, =3877. At 
18°, and when V=333, w, for H,SO,, according to Kohl- 
rausch, —600.2. In our experiments V=400. For V= 
400, , would lie between 600 and 610. 
In our solutions, therefore 
a= 344 =0.95 for HCl (25° ); 
a= hae os eee (25°); 
a= #12 = 0.8 (inaccurate) for H,SO, (18°). 
The effect which the presence of NaCl has on the dis- 
sociation of the acids is neglected in these values. 
If we study the figures somewhat more closely, we see 
that they are not far removed from unity; that, in other 
words, about 95 per cent. of the hydrochloric and the nitric 
acid molecules have dissociated into ions, and something less 
1OsTWALD, Lehrbuch, 2d ed., Vol. II, p, 675. 
2KouLRAUuSCH, Wiedemann's Annalen, Vol. L. 
Digitized by Microsoft® 
