Question

How do you write a balanced equation for this redox reaction using the smallest whole number coefficients?

The reaction occurs in aqueous acidic solution.

`"ClO"^(-)+"I"_2->"Cl"^(-)+"IO"_3^-`

Answer 1

Well try.....

`I_2 + 5ClO^(-) +H_2O rarr 2IO_3^(-) +5Cl^(-) +2H^(+)`

Explanation:

Hypochlorite is REDUCED.....`stackrel(+I)Clrarrstackrel(-I)Cl`

`ClO^(-) + 2H^+ + 2e^(-) rarr Cl^(-) +H_2O` `(i)`

Charge and mass are balanced, so tick.....

And elemental iodine is oxidized.....`stackrel(0)I_2rarrstackrel(+V)I`

`1/2I_2 + 3H_2O rarr IO_3^(-) +6H^(+) + 5e^(-)` `(ii)`

Charge and mass are balanced, so double tick.....

And so we take `5xx(i)+2xx(ii)`.........

`I_2 + 5ClO^(-) +H_2O rarr 2IO_3^(-) +5Cl^(-) +2H^(+)`

Is this balanced with respect to mass and charge? If it is not, then we may reject it out of hand!