Balance the given reaction by oxidation number method a.Cl2O7 + H2O2 ClO2- + O2 + H+ (basic medium) b.MnO4- + SO2 Mn2+ + HSO4- (acidic medium)
The oxidation number of chlorine decreases from +7 to +3 and the oxidation number of O increases from -1 to 0.SO CI2O7 is oxidizing agent and H2O2 is reducing agent .
ion electron method
the oxidation half reaction is H2O2--->O2
To balance oxidation number 2 electrons are added
H2O2--->O2+2e-
2 hydroxide ions are added to balance the charge
H2O2+2OH---->O2+2e-
2 water molecules are added to balance the O atoms
H2O2+2OH- --->O2+2H2O+2e-
the reduction half reaction is CI2O7-->CIO2-
THE CI atoms are balanced Cl2O7--->CIO2-
8 electrons are added to balance the oxidation number CI2O7+8e- -->CIO2-
6 hydroxide ions are added to balance the charge CI2O7+8e- --->CIO2-+6OH-
The oxidation half equation is multiplied with 4 and added to the reduction half equation.
oxidation number method
total decrease in oxidation number of CI2O7 is 8
total increase in oxidation number of H2O2 IS 2
H202 AND O2 are multiplied with 4
CI2O7+4H2O2--->CIO2-+4O2
Chlorine atoms are balanced CI2O7+4H2O2--->2CIO2-+4O2
O atoms are balamced by adding 3 water molecules CI2O7+4H2O2--->2CIO2- +4O2+3H2O
H atoms are balanced by adding 2 hydroxide ions and 2 water molecules.CI2O7+4H2O2+2OH- --->CIO2- +4O2+5H2O
