Q3(40%). About 80% of world Mg production is from electrolytic reduction of MgCl2. The electrolytic cell (IG cell) operates at 800C and the feed is anhydrous MgCl2. The anode-cathode spacing is 55mm. The conductivity of the molten salt is 2.3S/cm. The cell operates at a current density of 0.70Amps/cm2. The anode overvoltage is 0.50V, the cathode overvoltage is 0.05V, and the voltage drop in the busbar/electrodes is 1.30V (note: voltage drop in busbar is independent from Ohmic voltage drop due to conductivity of electrolyte and has to be accounted separately). The IG cell operates for a week at 35kA and 2400kg of Mg is recovered. The overall cell reaction is: MgCl2( as Mg2++2Cl)=Mg()+Cl2(g) The Cl2 gas is collected from the top. The specific gravity of magnesium (1.60 at 800C) is less than electrolyte so the liquid Mg also floats to the top for collection. The composition of the molten salt electrolyte is, by weight: 30%NaCl+12%MgCl2+13%KCl+45%CaCl2. 1) Write the anodic and cathodic reactions based on per mole of magnesium. 2) Calculate E for the cell. Assume pure magnesium; aMgCl2=XMgCl2 (mole fraction); PCl2=0.34atm 3) Determine the sodium, potassium and calcium concentrations in the liquid magnesium at electrochemical equilibrium. (hint: These parasite reduction reactions are not likely to significantly reduce the current efficiency). 4) Calculate the overall applied voltage. 5) Calculate current efficiency and the energy efficiency. 6) Calculate how much heat is transferred from the cell to the surroundings (in kW ). Hint: the amount of work (in kW ) done on system can be calculated by multiplying I Iapplied by Vapplied. All thermodynamic data: MgCl2,298=Mg1073+Cl2,1073H=704,010J/mole