What is the standard reducing potential `(E^(@))` for `Fe^(3+)to Fe`?
(Given that `Fe^(2+)+2e^(-)rightarrowFe,` `E_(Fe^(2+)//Fe^(@)) =-0.47V`
`Fe^(3+) + e^(-)to Fe^(2+)`, `E_(Fe^(3+)//Fe^(2+))^(@)= +0.77V`

Options

A. `-0.057` V
B. `+0.057` V
C. `+0.30` V
D. `-0.30` V

Answer

A

Explanation

`Delta G^(@) = - n FE^(@)`

`DeltaG^(0) = - nFE^(0)`
`E^(0)` for `(Fe^(3+) to Fe) = (Delta G^(0))/(-nF) = (0.17 F)/(-3F) = -0.057 V`