Assignment

1. Calculate the electrode potential of the Mg²⁺/Mg electrode when the concentration [Mg²⁺] = 0.01 M. (Standard potential E°_Mg²⁺/Mg = −2.36 V.)
2. Electrolysis problem: 100 mL of a neutral solution containing 0.2 g of copper was electrolysed until all the copper was deposited. The current was maintained at 1.2 A and the solution volume stayed 100 mL. Assuming 100% faradaic efficiency, find the time taken for complete deposition of copper. (Atomic weight of Cu = 63.58 g·mol⁻¹.)
3. The standard reduction potentials of the Cu²⁺/Cu and Ag⁺/Ag electrodes are +0.34 V and +0.80 V respectively. (a) Construct a galvanic cell using these half-cells and state the cell notation and expected cell reaction. (b) For what concentration of Ag⁺ will the emf of the cell at 25 °C be zero if [Cu²⁺] = 0.01 M?
4. Calculate the maximum (reversible) electrical work obtainable from the Daniel cell (Zn | Zn²⁺ || Cu²⁺ | Cu) using the standard free energies of formation (or absolute free energies) given for Zn(s), Cu(s), Cu²⁺(aq) and Zn²⁺(aq). Given that $E^0_{Zn^{2+}/Zn}$ and $E^0_{Cu^{2+}/Cu}$ are -0.76 and +0.34 V respectively.
5. For Daniel Cell involving the cell reaction, $Zn(s) + Cu^2+(aq) \rightleftharpoons Zn^2+(aq) + Cu(s)$, the standard free energies (ΔG°) are given as: Zn(s) = 0 kJ·mol⁻¹, Cu(s) = 0 kJ·mol⁻¹, Cu²⁺(aq) = +64.4 kJ·mol⁻¹, Zn²⁺(aq) = −154.0 kJ·mol⁻¹. Using these values, calculate the standard EMF E° of the cell.