Question

The electrode potentials for $Cu^{2+}(aq)+e^- \rightarrow Cu^+_{(aq)}$ and $Cu^{+}(aq)+e^- \rightarrow Cu_{(s)}$ are $+ 0.15 \,V$ and $+ 0.50\, V$ respectively. The value of $E^0_{Cu^{2+}/Cu}$ will be

• A. 0.325 V
• B. 0.650 V
• C. 0.150 V
• D. 0.500 V

Answer 1

Answer: (A)

0.325 V

Answer 2

$\Delta G _{3}=\Delta G _{1}+\Delta G _{2}$ $\Rightarrow-2\,FE ^{ o }=-1 F \times 0.15+(-1 F \times 0.50)$ $\Rightarrow-2 \,FE ^{ o }=-0.15\, F -0.50\, F$ $\Rightarrow-2 \,FE ^{ o }=- F (0.15+0.50)$ $\therefore E ^{ o }=\frac{0.65}{2}=0.325\, volt$