LAWS OF ELECTROLYTIC DISSOCIATION 15 



certain salt (tetraethyl ammonium iodide) in various solvents 

 having the same degree of dissociation. A simple relationship 

 between D and c, the corresponding concentration, was obtained 



D 



= = constant, 



or, for an electrolyte possessing the same degree of dissociation in various 

 solvents the corresponding "linear concentration^^ (i.e., the cube root 

 of the concentration) is proportional to the dielectric constant of the 

 solvent. It can be easily shown that the cube root of the concen- 

 tration of the solute is inversely proportional to the average distance 

 between any of its adjacent molecules. 



The ions of water have also very special properties. According to 

 the Rutherford-Bohr hypothesis of the atomic structure the H+- 

 ion consists of one positively charged atomic nucleus unaccom- 

 panied by any (negative) electron. It is the smallest mass aggre- 

 gate bearing a positive charge. The smallest negatively charged 

 body is the electron whose mass is only 1/1800-th of a H+-ion, and 

 an analogously small positively charged mass is unknown. In 

 addition to being the smallest known positively charged particle, 

 the H+-ion has the smallest atomic radius of any atomic structure. 

 Furthermore, since it has no shell of electrons surrounding it, it 

 can reach into closer proximity with negatively charged particles 

 than any other positive ion. Also, since the force of attraction of 

 opposite charges increases as the square of the distance, the H+-ion 

 can be held more firmly by negative ions than any other mono- 

 valent positive ion. 



The properties of the OH~-ion are not as easily explained on the 

 basis of the atomic model. There is a possibility of presenting 

 this entire question in a way which will obviate the necessity of 

 endowing the OH~-ion with special and extreme properties, and 

 which will permit the unique position of the H+-ion to suffice for 

 the elucidation of the problem. 



This particular way may be stated as follows: Of all electrolytes 

 in aqueous solution the acids and bases are the least dissociated. 

 Tl:ere are a few exceptions to this rule, HCl, HNO3, H2SO4, NaOH, 

 KOH, Ba(0II)2 and some others, which are just as strongly disso- 

 ciated as the salts. But most free acids and bases are weak electro- 

 lytes, while, as a general rule, the salts belong to the class of strong 



