Long Answer Type
1. Write the oxidation and reduction half-reactions by observing the changes in oxidation numbers and write these separately.
                     Â
Oxidation half-reaction: Â Â Â Â Â 
Reduction half-reaction: Â Â Â 
2. Balancing the oxidation half reaction.
(i) The balance I atoms are done by multiplying HIO3 by 2.
               0       +5
                
(ii) Add 10 electrons towards R.H.S. in order to balance the changes on iodine atoms.Â
                     
(iii) Balance the O atoms by adding six H2O molecules towards L.H.S.
              
(iv) Balance H atoms by adding ten H+ towardsÂ
R.H.S.
          
3. Balancing the reduction half reaction.Â
 (i) Balancing of N is not required as the number of each N is one on both the sides.Â
         +5          +4
        HNO3      
  NO2
(ii) Add one electron towards L.H.S. in order to balance the charges on the nitrogen atom.Â
         +5           +4
         HNO3 + e-  
  NO2
(iii) Balance O atoms by adding one H2O molecule towards R.H.S.
         5          4
        HNO3  + e-    
 NO2 + H2O
(iv) Â Balance H atoms by adding one H+ towards
L.H.S.
     +5              +4
    HNO3 + H+ + e-    
  NO2 + H2O
                   (Balance reduction half reaction)
4. Multiply balanced reduction half-reaction by 10 to equate electrons and add both the half reactions.Â
        
This is a balanced redox reaction.
Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess of chlorine is removed by treating with sulphur dioxide. Present a balanced equation for this redox change taking place in water.Â
The Mn3+ ions is unstable in solution and undergoes disproportionation to give Mn2+, MnO2 and H+ ion. Write a balanced ionic equation for the reaction.
Short Answer TypeLong Answer TypePermanganate (VII) ion, 
 in basic solution oxidises iodide ion, I- to produce molecule iodine (I2) and manganese (IV) oxide (MnO2). Write a balanced ionic equation to represent redox reaction.Â
Balance the following equations in basic medium by ion-electron method and oxidation number method:
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