[nattie]

hi all,
there are 2 things about this chemical process that i find confusing.
first, the cathode. is the cathode also the iron (which plays the part of an anode as well) or it is oxygen?
second, the equation of the reduction of oxygen (O_sub_2). sources dont seem to be agreed on this. some say O2 (g) + 2 H2O + 4e- ------> 4 OH- , others say O2 (g) + 4 H+ (aq) + 4e- ------> 2 H2O(l) . which one is more correct then?
i understand perfectly how a voltaic cell works; but when it comes to how this applies to corrosion (and rusting to be specific), i am completely lost, so any help would be appreciated. thanks a lot.

[vhpk]

Firstly, the material for cathode, it depends on you, it can be iron, platin, cooper, graphit, ect,...
Secondly, remember H2O is also an acid and base, so your reaction happens, it depends on what electrode you use.