Given,`{:(E_(Fe^(3+) //Fe)^o + 3e Cr E^o =- 0.036 V),(E_(Fe^(3+) //Fe)^o =- 0.439 V):}`
The value of standard electrode ptoential for the charge,

Options

A. 0.385 V
B. 0.770 V
C. `-0.270 V`
D. `-0.072`

Answer

B

Explanation

`Fe^(3+)+3e^(-)toFe" "triangleG_(1)=-3xxFxxF_(Fe^(3+)//Fe)^(0)`
`Fe^(2+)toFe" "triangleG_(2)=-2xxFxxE_(Fe^(2+)//Fe)^(0)`
`Fe^(3+)+e^(-)toFe^(2+)" "triangleG=triangleG_(1)-triangleG_(2)`
`triangleG=3xx0.036F-2xx0.439xxF=-1xxE_((Fe^(3+)//Fe^(+2)))^(0)xxF`
`E_((Fe^(3+)//Fe^(+2)))^(0)=2xx0.439-3xx0.036`
`=0.878-0.108`
`=0.770V`