LAWS OF ELECTROLYTIC DISSOCIATION 17 



NaOH is usually written as: NaOH -^ Na+ + 0H~, and it seems 

 indeed as if the H-ions play no part in it. But it is to be remem- 

 bered that the symbol Na+ does not represent the actual constitu- 

 tion of this ion. The ions are being constantly hydrated, and while 

 the changing number of molecules of the water of hydration (see 

 below) is not usually included in the formula for the Na+ ion, yet 

 a sjonbol including 1 molecule of H2O as (NaH20)+ is hardly less 

 justifiable than the sjanbol Na+. In this method of representation 

 the sodium ion arises from sodium hydroxide by the addition of a 

 H+ ion, and not by splitting of an 0H~ ion. 



NaOH + H+-^(NaH20) + 



Or, if it is not desirable to be restricted to the above formulation, 

 the same result can be represented as: 



NaOH + H+-^Na+ + H2O 



That is to say: one molecule of NaOH binds or otherwise employs 

 one H+ ion to form one Na+ ion with one molecule of H2O. In 

 this way the strong bases can be brought within the scope of the 

 above general definition of a base. 



If it be desired to include the amphoteric electrolytes in this same 

 general scheme, then they would be defined as molecular species 

 which are capable of both binding and yielding H-ions. If, for 

 example, glycocoll be designated as H-R-NH2, its double dissocia- 

 tion will be expressed as: 



1. H-R-NH2 + H+^(HRNH3)+ and 



2. H-R-NH2 > H+ + (RNHj)- 



Hitherto reaction 1 lias been usually written as 



H-R-NH2 + H2O -> H-R-NH3OH -^ (H-R-NH3)+ + OH- 



but the actuality of the molecular complex HRNH3OH is entirely 

 questionable. Therefore, there is the possibility of correlating all 

 aspects of acidity and alkalinity with the H+ ion without any 

 reference to the 0H~ ion. But this is only a possibility and not an 

 absolute necessity. Indeed, there are cases in which it is preferable 

 and easier to explain the formation of an anion by the addition of 



