i 



63i Mr. Bernard Cavanagh on 



the mass-action equation in its ordinary form. When ions 

 participate we get a modified equilibrium-equation. 



The case of a weak (or u semi-weak") monobasic acid HA 

 will suffice as an example. 



All the 6Vs are equal, but while 



g^=</>HA — R log C H a, 



the undissociated molecules behaving as a perfect solute ; 

 on the other hand, 



|* =<j>R ,-n log o H ,_ R2 ^±1 & of 1 ] 



0*1A' - J 



Whence we get 



lo g ~n = r o ■ -MWi + 1)^ U [105) 



= log K- 2(^i + l)0i'GT l , • • • (106) 



which, of course, might have been obtained from the fact 

 that 



locr 7 = iZ(m 1 + l)<j> 1 'C7\ 



where 7 is now the activity coefficient as distinct from the 

 "stoichiometric activity coefficient" generally used by 

 G. N. Lewis. ' 



For the very meaning of <y involves 



(7^h-)(7CaO 



c 



= K. 



HA 



High Concentrations of Electrolytes. 



The study of really high concentrations of electrolytes is 

 ( at present necessarily rather devoid of significance from the 

 point of view of this paper. 



Other inter-solute forces enter into the problem, besides 

 the electrostatic forces which no longer remain readily 

 amenable to dynamical calculation, and finally the solvent 

 must necessarily * be a polymerized one of little-known 



* As far as experience goes. 



