The half-reactions of reductants are:
COO
–
COO
–
5
10CO2 + 10e
–
5 Fe2+ ® 5 Fe3+ + 5e–
5NO2
– + 5H2O ® 5NO3
– + 10H+ + l0e–
10I– ® 5I2 + 10e–
The full reaction can be written by adding the half-reaction for
KMnO4 to the half-reaction of the reducing agent, balancing wherever
necessary If we represent the reduction of permanganate to manganate,
manganese dioxide and manganese(II) salt by half-reactions,
MnO4
– + e– ® MnO4
2–
(E
o = + 0 56 V)
MnO4
– + 4H+ + 3e– ® MnO2 + 2H2O
(E
o = + 1 69 V)
MnO4
– + 8H+ + 5e– ® Mn2+ + 4H2O
(E
o = + 1