The chemistry of corrosion is quite
complex but it may be considered
essentially as an electrochemical
phenomenon At a particular spot
(Fig 2 13) of an object made of iron,
oxidation takes place and that spot
behaves as anode and we can write
the reaction
Anode: 2 Fe (s) ¾® 2 Fe2+ + 4 e– 
o
(Fe2+
/Fe)
E
 = – 0