CARBONIC ACID 143 



+ 

 hydrogen by (H) and of ionized hydroxyl by 



(OH):- 



If (H) = 0.0000001N = (OH) 



the solution is neutral; 



if (H) > 0.0000001N > (OH) 



the solution is acid; 



if (H) < 0.0000001N < (OH) 



the solution is alkaline. 



It remains to point out that implicit in 

 these definitions is the well-founded hypothesis 

 that in water the concentrations of hydrogen 

 and hydroxyl ions vary inversely, so that 

 with constant temperature under all circum- 

 stances their product is constant : 1 — 



(H) X (OH) = K 



Substituting in this equation the value 

 0.0000001 of the concentrations at neutral- 

 ity, we obtain the value 



K = 0.00000000000001 

 whence (H) = 0,00000000000001 



(OH) 



1 This corresponds with the requirements of the Mass. 

 Law. 



