Question

The EMF of the cell,
$Mg|M{g}^{2+}(0.0IM)||S{n}^{2+}(0.1M)|Sn$ at $298K$ is
$\left(E_{M{g}^{2+}/Mg}^{\circ }=-2.34V,E_{S{n}^{2+}/Sn}^{\circ }=-0.14V\right)$

• A. 2.17 V
• B. 2.23 V
• C. 2.51 V
• D. 2.45 V

Answer 1

Answer: (B)

The cell reaction is
$Mg+S{n}^{2+}\to M{g}^{2+}+Sn$
$E_{\text{cell }}=E_{\text{cell }}^{\circ }-\frac{0.0591}{2}\log \frac{\left[M{g}^{2+}\right]}{\left[S{n}^{2+}\right]}$
$=(2.34-0.14)-\frac{0.0591}{2}\log \frac{10^{-2}}{10^{-1}}=2.23V$