REDOX REACTIONS
Introduction
Practically, all chemical reactions are carried out for the purpose of
generating energy. Combusion of fuels, generation of electricity by batteries
and even metabolism of food are redox (oxidation-reduction) reactions.
|
Oxidation : It is a process in which a substance (an ion
or an atom) loses one or more electrons.
Reduction : It is a process in which a substance (an ion
or an atom) gains one or more electrons.
|
Redox reaction : Electrons are not transferred to the surroundings in
ordinary chemical reactions but electrons lost by one species, must be gained by
another. Such chemical reactions involving loss of electrons by one species and
the simultaneous gain by another constitute (oxidation - reduction) redox
reaction.
Any redox reaction comprises two half reactions: one
corresponding to oxidation and the other to reduction.
Examples
1) 2Ca + O2
� 2CaO Half
reaction
2Ca - 4e-
� 2Ca+
2
(Oxidation)
O2 + 4e-
� 20-
2
(Reduction)
2) Na + 1 Cl2
� NaCl
2
Na - e-
� Na+
(Oxidation)
1 Cl2 + e-
� Cl-
(Reduction)
2
A Redox reaction can be represented as
|
