`E_(cell)^(@)` for the cell:
`Pt(s) | Fe^(2+)(aq)|Fe^(3+)(aq)||MnO_(4)^(-)(aq), H^(+)(aq)|Mn^(2+)(aq)|Pt` is 0.8 volt.
[Given: `DeltaG_(f)^(@), H_(2)O(l) = -230 kJmol^(-)`
`DeltaG_(f)^(@), Fe^(3+)(aq) = 10.2kJ mol^(-)`
`DeltaG_(f)^(@), Mn^(2+)(aq) = -229 kJmol^(-)`
`DeltaG_(f)^(@), Fe^(2+)(aq) = -84kJmol^(-1)]`
Determine magnitude of `DeltaG_(f)^(@)`, `MnO_(4)^(-)`(aq) in `kJ mol^(-)`
