O2 + 2H2O + 4 e-------> 4OH- is + 0.40V
For other half-reactions, use a textbook. Calculate E for this cell.
b). Use your value from part a) to calculate the dissociation constant at 298K.
We need H2O ----> H+ + OH- E = ?
O2 + 2H2O + 4 e-------> ...
The dissociation constant of water is calculated from electrochemical diagrams.