What is the standard reduction potential $\left({\text{E}}^{\text{o}}\right)$ for $\text{F}{\text{e}}^{3+}\to \text{F}\text{e}?$

Given that:

$\text{F}{\text{e}}^{2+}+2{\text{e}}^{-}\to \text{F}\text{e};{\text{E}}_{\text{F}{\text{e}}^{2+}/\text{F}\text{e}}^{\text{o}}=-0.47\text{V}$

$\text{F}{\text{e}}^{3+}+{\text{e}}^{-}\to \text{F}{\text{e}}^{2+};{\text{E}}_{\text{F}{\text{e}}^{3+}/\text{F}{\text{e}}^{2+}}^{\text{o}}=+0.77\text{V}$

• Correct answer
  A

  $-0.057\text{V}$
• B

  $+0.30\text{V}$
• C

  $-0.30\text{V}$
• D

  $+0.057\text{V}$

Hence, the correct answer is option: 'A'.