Using the standard electrode potentials given, predict if the reaction between the following is feasible:
`Fe^(3+)(aq)` and `l^(-)(aq)`
Fe3+/Fe2+ : +0.77 V
I-/I2 : -0.54 V

Explanation

We know that an electrode with higher reduction potential is cathode and an electrode with lower reduction potential in an electrochemical cell is called anode. Making use of this concept, let us determine the `E^(Theta)` of the cell. If `E^(Theta)` is positive, the reaction is feasible otherwise not.
(a) `I_(2)(s)+2e^(-) to 2I^(-)(aq) E^(Theta)=0.54V`
`underset(-)2Fe^(3+)(aq)+underset(-)(2e^(-)) to underset(-)(2Fe^(2+)) (aq) E^(Theta)=underset(-)(0.77)V`
Subtracting we get
`I_(2)(s) -2Fe^(3+)(aq) to 2I^(-)(aq)-2Fe^(2+)(aq) E^(Theta)= -0.23V`
or `I_(2)(s) +2Fe^(2+)(aq) to 2Fe^(3+)(aq) +2I^(-) (aq) E^(Theta)=-0.23V`
or `2Fe^(3+)(aq) +2I^(-)(aq) to I_(2)(s) +2Fe^(2+) (aq) E^(Theta)= +0.23V`
Since `E^(Theta)` is positive, the reaction is feasible.