The correct option is B IO−4+7I−+8H+→4I2+4H2O
The unbalanced redox equation is as follows:
IO−4+I−+H+→I2+H2O
All atoms other than H and O are balanced.
The oxidation number of iodine changes from -1 to 0. The change in the oxidation number of iodine is 1.
The oxidation number of iodine changes from +7 to 0. The change in the oxidation number of iodine is 7.
The increase in the oxidation number is balanced with decrease in the oxidation number by multiplying
I− and I2 with 7.
IO−4+7I−+H+→4I2+H2O
O atoms are balanced by adding 3 water molecules on RHS.
IO−4+7I−+H+→4I2+4H2O
Hydrogen atoms are balanced by adding 7 H+ atoms on the RHS.
IO−4+7I−+8H+→4I2+4H2O
This is the balanced chemical equation.