Question

Given standard electrode potentials.

$\rightarrow$

$\rightarrow$

The standard electrode potential $\rightarrow$ for

$\rightarrow$ is.

• A. – 0.476 V
• B. – 0.404 V
• C.
  • 0.404 V
• D.
  • 0.771 V

Answer 1

Answer: (D)

• 0.771 V

Answer 2

$\Delta G^{o} = - nE^{o}F$

$Fe^{2 +} + 2e^{-} \rightarrow Fe$ …..(i)

$\Delta G^{o} = - 2 \times F \times ( - 0.440V) = 0.880F$

$Fe^{3 +} + 3e^{-} \rightarrow Fe$ …..(ii)

$\Delta G^{o} = - 3 \times F \times ( - 0.036) = 0.108F$

On subtracting equation (i) from (ii)

$Fe^{3 +} + e^{-} \rightarrow Fe^{2 +}$

$\Delta G^{o} = 0.108F - 0.880F = - 0.772F$

$E^{o}$ for the reaction

$= - \frac{\Delta G^{o}}{nF}$ $= - \frac{( - 0.772F)}{1 \times F} = + 0.772V$.