In the first place, the law of chemical equilibrium is based thermodynamically, ‹i.e.› from the point of view of the ultimate energy relations involved, on the assumption that none but negligible forces of attraction or repulsion exist between the molecules, whose concentrations are factors in the equilibrium equations (‹cf.› p. 95).[200] Now, in solutions of electrolytes this condition is not strictly fulfilled under any circumstances; the attractions between ions of opposite charge and the repulsions of ions of like charge, as well as the effect of charged particles on neutral molecules, come into play. For strong electrolytes, where the proportion of charged particles is always a large one, the deviations from the simpler conditions to which alone the law is really applicable must be very much greater than for weak electrolytes. It is, therefore, probable that these electrical forces[201] are the source of the deviation of the ionization of strong electrolytes from the law of chemical equilibrium: although ionization is a reversible reaction, forces come into play which make the ‹simple law inapplicable›, and it is altogether likely, therefore, that we shall find, when all the factors have been investigated, that strong electrolytes should not and cannot obey ‹this law alone›.[202] In confirmation of this conclusion, recent careful calculations[203] have shown that entirely analogous deviations from the equilibrium law become perceptible in rather ‹concentrated› solutions of weak electrolytes, such as acetic acid, in which there is an accumulation of charged particles, more nearly akin to that present in ‹dilute› solutions of strong electrolytes. So it appears more and more certain that the deviations are a result of the presence of electrically charged components in the solutions, the amount of deviation depending on their concentration. «The "Salt Effect".»—In the second place,[204] it seems possible that the presence of strong electrolytes in a solution may modify the ‹ionizing power of the solvent› in such a way as to increase it, and to increase it the more, the more concentrated the ions are in the solution.[205] The ionizing power of solvents, as has been explained, is intimately connected with their dielectric properties. [p110]