Question
Balance the following chemical equation by oxidation number method:
in acidic medium.
Solution
(i) The skeleton equation along with oxidation number of each atom is
(ii) Noting the change in O.N. of above atoms
Increase Zn = 0 to +2 i.e 2
Decrease N = +5 to -3 i.e. 8
(iii) Equalise the increase/decrease O.N. by multiplying Zn by 4 and 
by 1.
(iv) Balance Zn atoms by multiple Zn2 ion by 4.
(v) Balance the oxygen atoms by adding three H2O molecules on the right-hand side. 
(vi) Balancing the hydrogen atoms by adding 10H+ ions on the reactant side. The complete balanced equation is
