Specific conductivity as a function of temperature, concentration and density

1 Specific conductivity as a function of temperature, concentration and density 

All die electrolytes show a maximum in the specific conductivity as plotted as a function of temperature at constant concentration and pressure (see Figme 4.4). The initial increases of k with temperature is due to the increase in the mobility of the ions as the viscosity and dielectric constant of water decreases. At high temperature the ion association reduces the munber of fiee ions and coimterbalances the increasing mobility. 

Valyashko and Ivanov (1979) noted that the maximum of the isothermal specific conductivity as a fimction of concentration is related to the charge, hydration, and degree of association of the electrolyte. Thus, electrolytes with the same charge-type have conductivity maximum in the same concentration range. Increasing hydration leads to a decrease in the concentration of file maximum. 

When plotted as a function of pressure the specific conductivity of dilute electrolytes increases slightly with pressure at temperatures below the critical point. Above the critical point the specific conductivity decreases sharply with decreasing density. The behavior pattern is simpler as the specific conductivity is plotted as a function of density. In that case the specific conductivity goes through a maximum at temperatures above the critical point but the curves for different temperatures remain close together. 

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