27MnO−4+6−1I−+4H2O→2+4MnO2+30I2+8OH−
Here, oxidation state of Mn decreases from +7 in KMnO4 to +4 in MnO2
n- factor of KMnO4=change in oxidation number per formula unit=3
oxidation state of I increases from −1 in I− to 0 in I2
now, n- factor of I2=change in oxidation number per I2 molecule=2
Since, n-factor×Number of mol(n)=number of g-equivalents
and at completion of reaction,
g-equivalents of KMnO4 consumed = g-equivalents of I2 formed
So, 3×molofKMnO4=2×molofI2
3×4=2×molofI2
Amount of I2=6mol