Question

On the basis of the following $E^o$ values, the strongest oxidising agent is:
${\left[Fe{\left(CN\right)}_6\right]}^{4-}⟶{\left[Fe{\left(CN\right)}_6\right]}^{3+}+e^{-},E^o=-0.35V$
${Fe}^{2+}\to {Fe}^{3+}+e^{-1}$;
${Fe}^{2+}\to {Fe}^{3+}+e^{-1};E^o=-0.77V$

• A. ${Fe}^{3+}$
• B. ${\left[Fe{\left(CN\right)}_6\right]}^{3-}$
• C. ${\left[Fe{\left(CN\right)}_6\right]}^{4-}$
• D. ${Fe}^{2+}$

Answer 1

Answer: (A)

For the strongest oxidizing agent, the oxidizing potential should be least. Here, the oxidizing potential of ${Fe}^{+2}$ is less than that of ${\left[{Fe\left(CN\right)}_6\right]}^{4-}$. Therefore, ${Fe}^{+2}$ is stronger oxidizing agent than ${\left[{Fe\left(CN\right)}_6\right]}^{4-}$. Also, the stronger oxidizing agent should easily reduce itself. Here, ${Fe}^{+3}$ is easily reduced than ${Fe}^{+2}$. Therefore, among all the four, ${Fe}^{+3}$ is the stronger oxidizing agent.