Find the standard electrode potential of `MnO_(4)^(c-)|MnO_(2).` The standard electrode potential of `MnO_(4)^(c-)|Mn^(2+)=1.51V` and `MnO_(2)|MnO_(2)|Mn^(2+)=1.23V`.

Explanation

Given`:`
b `{:(i.,MnO_(4)^(c-)+8H^(o+)+5e^(c-),rarr,Mn^(2+),+,4H_(2)O),(ii.,MnO_(2)+4H^(o+)+2e^(-),rarr,Mn^(2+),+,2H_(2)O):}] {:(DeltaG_(1)^(c-)),(DeltaG_(2)^(c-)):}`
Equation `(i)` and `(ii)` give the required equation `,i.e.,`
`MnO_(4)^(c-)+4H^(o+)+3e^(-) rarr MnO_(2)+2H_(2)O]DeltaG_(3)^(c-)`
`:. DeltaG_(3)^(c-)=DeltaG_(1)^(c-)-DeltaG_(2)^(c-)`
`-3FE_(3)^(c-)=-5FE_(1)^(c-)-(-2FE_(2)^(c-)-(-2FE_(2)^(c-))`
`(` or `)` Use direct relation `:`
`E_(2)^(c-)=(n_(1)E_(1)^(c-)-n_(2)E_(2)^(c-))/(n_(3))`
`=((5xx1.51)V-(2xx1.23)V)/(3)`
`E_(3)^(c-)=1.7V`