Determination of electrochemical reaction orders from the charge transfer resistance

2 Determination of electrochemical reaction orders from the charge transfer resistance 

The equations for the exchange current density of the complex redox reaction are 

From these equations one can derive equations for the concentration dependence of the exchange current density. The Nemst potential is substimted by concentrations according to Eq. (6.30). Setting concentrations approximately equal to activities one obtains 

This autocatalytic mechanism explains the autocatalytic action of HNO2 on the reduction of nitric acid. 

The nitrous acid-nitiic acid redox system is an example of a controversy in the hterature. The above mechanism was developed by Vetter from one of the first applications of the concept of electrochemical reaction orders on a redox system. G. Schmid - intuitively suggested another mechanism based on a charge transfer reaction 

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