HYDROLYSIS

131

i.e.

a

- = const.

salt

The essential difference is, therefore, that the concentra-
tion of the salt enters as the second power instead of the
first.

In this case, therefore, unlike the other, the hydrolysis
is independent of the dilution.

The following table contains data for aniline-acetate,
which confirm this result1. The hydrolyzed fraction, as
determined by the conductivity, is given under s, while V
is the volume in litres containing one gram-molecule of
aniline-acetate:

V 12-5 25
s 0-454 0-442

50
0.436

IOO

0.449

200

0444

4OO
0-446

800

0-431

The constancy of s is in agreement with the above formula.
Before going further with the calculations in this con-
nexion, we will consider a chief factor in the phenomena
of hydrolysis—the dissociation of water itself.
(§) Electrolytic dissociation of water a/nd hydrolysis.
If one is not previously convinced of the correctness of the
electrolytic dissociation theory, hardly any result won by
means of it is so convincing as the agreement between
the conclusions drawn in completely different ways as
to the degree of dissociation of water itself.
Ostwald2 calculated it at i x io*7 at 25° on the basis of
a measurement of the electromotive force of an oxygen-
hydrogen battery; i.e. in a litre i x io~7 gram-molecule
+ —
would be present as the ions H and OH.
Arrhenius3 arrived at the value i-i x io~7 from Shields'
measurements of the hydrolysis of salts.
1 Arrhenius-Walker, Zeitschr.f. Phys. Chem. 5. 20.
* Ber. d. Jcgl. s&chs. Ges. d. Wiss., Jan. 93 j Zeitsckr.f. Phys. Chem. 11. 521 ;
Kernst, 1. e. 14. 155.
8 Ber. d. Ugl. schwed. Akad. d. Wiss., Feb. 93; Zeitstfvr, /. Phys. Chem. n.
827 ; Bredig, 1. a n. 829.
I 2,