Question

$Zn|Z{n}^{2+}(C_1)||Z{n}^{2+}(C_2)|Zn$ . For this cell $\Delta G$ is negative if

• A. $C_1=C_2$
• B. $C_1>C_2$
• C. $C_2>C_1$
• D. None of these

Answer 1

Answer: (C)

$Anode:Zn\to Z{n}^{+2}\left(C_1\right)$

Cathode: ${\mathrm{Zn}}^{+2}\left({\mathrm{C}}_2\right)\to \mathrm{Zn}$

$K_c=\frac{\left(Z{n}^{+2}\right)A}{\left(Z{n}^{+2}\right)C}=\left(\frac{C_1}{C_2}\right)$

$E=E^o-\frac{0.0591}{2}log{k}_c$

$\Delta G=-nFE$

$E=E^{\circ }-\frac{0.0591}{2}log\frac{C_1}{C_2}=\frac{0.0591}{2}log\frac{C_2}{C_1}$

to make $\Delta G=-ve$

$\Delta E=+ve$ hence, $C_2>C_1$