Chemistry Electrochemistry 5 Marks
Appeared in: 2023 (2 sets)
(a) (i) State Kohlrausch's law of independent migration of ions. Write an expression for the limiting molar conductivity of acetic acid according to Kohlrausch's law. (ii) Calculate the maximum work and $\log K_c$ for the given reaction at $298 \text{ K}$: $\text{Ni (s)} + 2\text{Ag}^+ \text{(aq)} \rightleftharpoons \text{Ni}^{2+} \text{(aq)} + 2\text{Ag (s)}$ Given: $E^\circ_{\text{Ni}^{2+}/\text{Ni}} = -0.25 \text{ V}$, $E^\circ_{\text{Ag}^+/\text{Ag}} = +0.80 \text{ V}$, $1 \text{ F} = 96500 \text{ C mol}^{-1}$. OR (b) (i) State Faraday's first law of electrolysis. How much charge, in terms of Faraday, is required for the reduction of $1 \text{ mol Cu}^{2+}$ to $\text{Cu}$? (ii) Calculate emf of the following cell at $298 \text{ K}$ for $\text{Mg (s)} \mid \text{Mg}^{2+} (0.1 \text{ M}) \parallel \text{Cu}^{2+} (0.01 \text{ M}) \mid \text{Cu (s)}$ $[E^\circ_{\text{cell}} = +2.71 \text{ V}, 1 \text{ F} = 96500 \text{ C mol}^{-1}, \log 10 = 1]$