Hi. I have a lab that concerns this reaction as follows: S2O8 2- + 2e- = 2SO4 2- Can anyone give me a hint as to why this reaction would NOT (and indeed does not as found in the lab) have a potential of ~ 2V from the H+/H2 reference? What is preventing the reaction from reaching its maximum? Attempts: 1) I've tried looking at http://hyperphysics.phy-astr.gsu.edu/hbase/tables/electpot.html and figuring something out but nothing seems to work. No extra information is given. 2) Is equilibrium reached? Thank you.