CBSE Class 12 Chemistry — Electrochemistry

What will happen during the electrolysis of aqueous solution of CuCl₂ by using platinum electrodes?

(a) Answer the following: (3 × 1) (i) Why is the Equilibrium Constant (Kc) related to E°cell and not to Ecell? (ii) Two metals 'A' and 'B' have standard electrode potential values of −0.24 V and +0.80 V respectively. Which of these will liberate hydrogen gas from dil. H₂SO₄? (iii) Write the cell reaction which occurs in lead storage battery when it is in charging. OR (b) What type of battery is Mercury cell? Why it is more advantageous than dry cell? Write overall reaction taking place in Mercury cell.

(a) Calculate emf and $\Delta G$ for the following cell at 298 K: $Mg(s) / Mg^{2+}(0.01\text{ M}) // Ag^+(0.001\text{ M}) / Ag(s)$ Given: $E^\circ(Mg^{2+}/Mg) = -2.37 \text{ V}$, $E^\circ(Ag^+/Ag) = +0.80 \text{ V}$ [$1F = 96500 \text{ C mol}^{-1}$, $\log 10 = 1$] OR (b) For the reaction: $2AgCl(s) + H_2(g) (0.4\text{ atm}) \to 2Ag(s) + 2H^+(0.1\text{ M}) + 2Cl^-(0.2\text{ M})$ Calculate emf of the cell at 25 °C. Given: $\Delta G^\circ = -43500 \text{ J mol}^{-1}$ [$\log 10 = 1$, $1F = 96500 \text{ C mol}^{-1}$]