A solution contains `Fe^(2+), Fe^(3+)` and `T^(-)` ions. This solution was treated with iodine at `35^(@)C. E^(@)` for `Fe^(3+), Fe^(2+)` is `0.77 V` and `E^(@)` for `I_(2)//2I^(-)` = 0.536 V. The favourable redox reaction is:

Options

A. `I_(2)` will be reduced to `I^(-)`
B. There will be no redox reaction
C. `I^(-)` will be oxidised to `I_(2)`
D. `Fe^(2+)` will be oxidised to `Fe^(3+)`

Answer

C

Explanation

The reaction will take place for which `E_("cell")^(@)` is positive.
(A) `I_(2)+2e^(-)rarr2I^(-),E_("red")^(@)=0.536V`
`Fe^(2+)rarrFe^(3+)+e^(-),E_("red")^(@)=0.77V`
`therefore E^(@)` will be -ve
(B) Reaction will occur
(C) `2I^(-)rarrI_(2)+2e^(-),E_("OX")=-0.536V`
`Fe^(3+)+erarrFe^(2+),E_("red")^(@)+0.77V`
`2Fe^(3+)+2I^(-)rarr2Fe^(2+)+I_(2),E_("cell")^(@)=+1.64V`
Thus `E^(@)` is +ve, this reaction will occur
(D) will not occur