If `e_(Fe^(2+) //Fe)^@ =- 0. 44 1V`. And `E_(Fe^(3+)//Fe^(2+))^(o) = 0. 771 V`. The standard emf of the reaction ` Fe +2 Fe^(3+) rarr 3Fe^(2+)` will be .

Options

A. ` 1. 653 V`
B. ` 0.11 V`
C. ` 0.330 V`
D. ` 1.212 V`

Answer

D

Explanation

`Fe rarr Fe^(2+) + 2e^(-) Delta F_1^@ =- 2 F xx 44 1`
`2 F^(3+) +2e^- rarr Fe^(2+) Delta G_2^@ =- 2 Fxx . 771`
`Fe +2 Fe^(3+) rarr Fe^(2+) Delta G-2^@ =- 2 FE_3^@ Delta G_1^@ +Delta G_2^@`
` =- 2 F xx 0. 44 1 - 2 F xx 0. 77 1`
`E_3^! = 1. 212 V`.