Para saber si se lleva a cabo una reacción donde un metal desplaza a otro metal de su sal u otro compuesto, es preciso:

The least electronegative component in the electron transport chain is the Hydrogen ion. 
The more electronegative is NAD+
The other component is H2O,
Next are the energy carrier molecules which are the ADP and ATP
And finally, the most electronegative is O2.