In an @[email protected], when reactants or @[email protected] are adsorbed, the @[email protected] may no longer be related to the @[email protected] by a simple law. The @[email protected] may be due to either entropic or energetic effects or both. The situation best understood is that where a reactant is non-specifically adsorbed in the outer Helmholtz plane (inner boundary of the @[email protected]). The effect of such @[email protected] on electrode kinetics is usually termed the Frumkin effect. @[email protected], transfer coefficients etc. corrected for this effect are frequently called 'true' rate constants etc. It would be preferable to describe them as 'corrected for the Frumkin effect', but in any case, if such a correction is carried out, the basis on which it is made should be clearly described.