23 V
E
The overall reaction being:
2Fe(s) + O2(g) + 4H+(aq) ¾® 2Fe2 +(aq) + 2 H2O (l)    
o
E(cell)
=1 67 V
The ferrous ions are further oxidised by atmospheric oxygen to
ferric ions which come out as rust in the form of hydrated ferric oxide
(Fe2O3 x H2O) and with further production of hydrogen ions Prevention of corrosion is of prime importance