Slightly associated electrolytes

From what has been said, eqn. 5.3.4 is clearly a two-parameter equation (A° and since and J2 do not depend on the electrolyte. If association is purely electrostatic, the two parameters are finally A° and a, the latter being obtained from Ka by means of eqn. 5.3.8. The fact tW only two parameters are adjustable in eqn. 5.3.4 is especially important when dealing with slightly associated electrolytes. 

For electrolytes having Ka < 20 mol 1, the precise value found from conductance measurements for the association constant is to a certain extent dependent upon the theory used to express /i and /2- A more important difficulty arises many times when eqn. 5.3.4 is employed for slightly associated electrolytes as a three-parameter equation. It is usual... 

At low ionic strength, the association—dissociation equilibria of H+ and OH- are only slightly affected by the presence of the electrolyte. However, when the sodium acetate concentration increases, Na+ ions compete with the H+ ions for adsorption on the acidic sites (the adsorption of the acetate ion on the basic sites is neglected). The corresponding equilibria are... 

Transfer of aqua electrolytes in polymers has characteristics [22] that distinguish it from the transfer of other low-molecular-weight matter. The presence of water in the medium sorbed may result in formation of aqua associates and electrolyte in the polymer. Depending on the amount of sorbed water, the polymers are subdivided into three groups (i) hydrophobic, i.e. slightly swelling in water (water concentration in the polymer below 0.5%), (ii) mildly hydrophilic (water concentration 0.5-10%), (iii) hydrophilic (water concentration above 10%). This subdivision is very conventional since the permeability mechanism depends not only on water concentration in the polymer but on the nature of their physical-chemical interactions with electrolyte ions and macromolecular active centers as well [23]. 

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