Electrochemical reactions time frames

The appearance of chemical reversibility depends on the rate of the following reaction in comparison to the time-scale of the experiment. Thus it is appropriate to consider the time frames of various electrochemical techniques (see Table 1). Maximum information is gained about electrode mechanisms when the electrochemical process is investigated over a range of time-scales, usually by more than one technique. 

If the concentration of K in the amalgam is not too high and there is no significant reaction with water during the time frame of the experiment, the electrode on the right-hand side provides a non-polarizable system which responds to the K" " ion activity in solution. The condition for the electrochemical equilibrium is... 

Second, Eh s and Eh s generally agree even for the first data point, typically taken about 5 min. after addition of FeCl3. This means that the electrode and solution are in electrochemical equilibrium within this time frame. This, in turn, indicates that all hydrolysis and chloride complexation reactions are essentially complete within 5 min., even at very low iron activities, consistent with the limited literature on this subject (50,M). 

---