Question

The electrode potentials for:

$C{u}^{2+}\left(aq\right)+e^{-}\to C{u}^{+}\left(aq\right)$
$C{u}^{+}\left(aq\right)+e^{-}\to Cu\left(s\right)$ are + 0.15 V and 0.50 V respectively. The value of $E^{0}c{u}^2/Cu$ will be :

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

Answer 1

The correct option is C 0.325 V

For the reaction $C{u}^{2+}\left(aq\right)+2e^{-}\to Cu\left(s\right)$, the number of electrons $n=2$.
For the reaction $C{u}^{2+}\left(aq\right)+e^{-}\to C{u}^{+}\left(aq\right)$, the number of electrons $n=1$.
For the reaction $C{u}^{+}\left(aq\right)+e^{-}\to Cu\left(s\right)$, the number of electrons $n=1$.

$n\times E_{C{u}^{2+}|Cu}^0=n\times E_{C{u}^{2+}|C{u}^{+}}^0+n\times E_{C{u}^{+}|Cu}^0$

$2\times E_{C{u}^{2+}|Cu}^0=1\times 0.15V+1\times 0.50V$
$2\times E_{C{u}^{2+}|Cu}^0=0.65V$
$E_{C{u}^{2+}|Cu}^0=0.325V$