60 
CHEMISTRY: J. KENDALL 
Proc. N. A. S. 
in complex "addition compounds" the attractive forces between the 
radicals are so diminished that disintegration of the complex into op- 
positely charged ions may readily occur. Union with another molecule 
promotes ionization. 
The theoretical arguments in favor of this assumption and the experi- 
mental evidence in its support cannot be presented in detail here. The 
immediate consequence of the modified ionization theory, as connected 
with the anomaly of strong electrolytes, may however be indicated. 
Instead of a simple equilibrium such as KCl K + + Cl~ for a uni- 
univalent electrolyte in aqueous solution, we now have to consider a 
complicated series of equilibria between many different molecular and ionic 
types, such as (KCl) x \ (KCl) x , (H 2 0) y ; [{KCl) x , CI]-, [(H 2 0) y , CI]-, 
etc. To some of these equilibria the law of mass action alone may apply, 
to others the Milner-Ghosh conception of electrostatic equilibrium may 
need to be superadded. Little wonder, therefore, that the problem has 
baffled all attempts at explanation under the hypothesis RX ~ R + + 
X~. If we persist in postulating the reaction as inconceivably simple, 
we can hardly expect to make progress, even in the field of dilute solu- 
tions, where many of the equilibria may be neglected. 
It might seem that the complexity in the equilibria necessarily intro- 
duced by the consideration of so many molecular types could, after all, 
only make the problem still more intricate and elusive. The first effect, 
nevertheless, is in the opposite direction. Many subsidiary assumptions 
which have been attached to our theory of solutions in order to conceal the 
failure of the simple equation RX ^ R + + X~ may now be shown to 
be unnecessary. For example, the hypothesis of the "catalytic activity 
of the undissociated molecule," which purports to explain why the speed 
of reactions such as ester catalysis is not exactly proportional to hydrogen 
ion concentration, may be discarded in favor of a view which recognizes 
several types of "hydrogen ion" (e. g., H+, [H(H 2 0)]+, [HiR.COOR 1 )]*) 
each possessing a different catalytic activity. In the same way abnormal 
results in electromotive force measurements, which have been interpreted 
as demonstrating a variable activity of the hydrogen ion with concentra- 
tion, may now be alternatively referred to variations in the ratios of the 
different types of "hydrogen ion" with concentration. There is no more 
reason, for instance, why the ion [H(H 2 0) x ] + should show the same 
potential difference as the ion H + with respect to gaseous hydrogen than 
there is for the ion [Cu(NH z ) y ] ++ to exhibit the same potential difference 
as the ion Cu ++ with respect to metallic copper. The extension of the 
theory of complex ions to simple aqueous solutions is evidently one of the 
first steps to be taken in the further development of the views here pre- 
sented. Detailed discussion must be postponed to a later article. 
Salts in Aqueous Solution. — The correlation of compound formation 
and ionization in this important field offers difficulties. Nearly all uni- 
