The Proportionality Constant Relating Electric Field and Current Density Specific Conductivity

The Proportionality Constant Relating Electric Field and Current Density Specific Conductivity 

In the case of small fields, the steady-state flux of ions can be considered proportional to the driving force of an electric field (see Section 4.3.2), i.e.. 

The quantity J is the number of moles of ions crossing a unit area per second. When J is multiplied by the charge borne by 1 mole of ions zF, one obtains the current density i, or charge flux, i.e., the quantity of charge crossing a unit area per second. Because i has direction, it will be written as a vector quantity, j. 

The constant zFB can be set equal to a new eonstant r, whieh is known as the specific conductivity (Table 4.7). The relation between the current density i and the electric field X is therefore 

The electric field is very simply related (Fig. 4.50) to the potential difference across the electrolyte, ip / - y/, [seeEq. (4.119)], 

---