CHAPTER I 

 The Laws of Electrolytic Dissociation 



SUMMARY 



The equilihrium of chemical reactions is governed hy the law of 

 mass action. Only in the case of dilute solutions can this law be sim- 

 ply and at the same time accurately formulated. This law can also 

 he applied to the dissociation of electrolytes and to the particular case 

 of the dissociation of water. The properties of the ions of water lead 

 to peculiarly specific results. All electrolytes which split off one of 

 the two ions of water change the state of dissociation of water; these 

 are the acids and bases. The concentration of H- or OH-ions in an 

 aqueous solution determines its acid or alkaline character respectively. 

 The strength of the acids and bases depends closely upon their disso- 

 ciation constants. The method of calculating the H-ion concentra- 

 tion from the concentration and strength of acids and bases in solu- 

 tion is described, and the development of the theory of regulators or 

 buffers is traced. Thr'ough the introduction of special functions of 

 H-ion concentration, of the degree of dissociation and of the dissocia- 

 tion residue, the laws of dissociation are reduced to a practically usable 

 form, leading to an explanation of the dissociation of amphoteric elec- 

 trolytes and to a conception of the isoelectric point. A discussion of 

 the dependence of the solubility of slightly soluble salts upon the H- 

 ion concentration and of the hydrolysis of salts is presented. 



1. The law of mass action 



The "law of mass action," as its name implies, is an expression of 

 the effect of the masses of the substances involved in a chemical 

 reaction upon this reaction. Its data relate to the establishment 

 of a definitive state towards which the chemical system is tending, 

 or, to the chemical equilibrium. This state of chemical equilibrium 

 is characterized by the fact that the amounts of the various kinds 

 of participating molecules remain unchanged with the time. It is 

 not, however, a condition of chemical rest, but rather a stationary 



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