Question 5 (20 Marks) Nickel metal is produced in Kwinana, WA by the reduction of the tetrammine complex Ni(NH3)42+ by hydrogen gas under pressure. (a) Calculate the equilibrium hydrogen pressure (in atmospheres) required to precipitate 90% of the nickel from a solution containing 1.0mol/1 nickel as the above complex and 1.0mol/1 free ammonia (NH3) at a pH of 11 at 25C. Assume ideal solutions and gases. Ni2++2e=NiNi2++4NH3=Ni(NH3)42+RT/F=0.059V/decadeE0=0.26VvsNHElog10K=7.7 [12 marks] (b) Suggest two changes to the operating conditions which would increase the degree of precipitation