Question

For the cell reaction $2 Ce^{4+}+Co \rightarrow 2 Ce^{3+}+Co^{3+} ; E^{\circ}_{cell}$ cell is $1.89\, V$. If $E_{Co^{2+}/Co}$ is $- 0.28 \,V$, what is the value of $E^{\circ} _{Ce^{4+}/Ce ^{3+} }$?

• A. 0.28 V
• B. 1.61 V
• C. 2.17 V
• D. 5.29 V

Answer 1

Answer: (B)

1.61 V

Answer 2

$E_{\text {cell }}^{\circ}=E_{\text {ox }}^{\circ}+E_{\text {red }}^{\circ}=-E_{ Co / Co ^{2+}}^{\circ}+E_{ Ce ^{4+} / Ce ^{3+}}$ $1.89=-(-0.28)+E_{ Ce ^{4+} / Ce ^{3+}}^{\circ}$ $\therefore E_{ Ce ^{4+} / Ce ^{3+}}^{\circ}=1.89-0.28=1.61\, V$