2. Comparing CSTR and PFR performance: a) A drinking water treatment plant is using an oxidant called permanganate (MnO4) to oxidize Fe2+ to Fe3+, to prevent rust formation downstream. Assume that the hydraulic residence time in the permanganate reactor is 10 minutes, that the permanganate concentration is 2 mM and is steady throughout the process, and that the reaction rate constant for the reaction between iron and permanganate is 5 M's? If the initial Fe2+ concentration is 100 uM, what is the final Fe2+ concentration at the end of the reactor if it behaves like a PFR? b) What if the reactor were a CSTR (same parameters as above)? c) How many CSTRs in series would be needed to reach a final Fe2concentration of 0,5 HM? Round your answer to the nearest integer Hint: don't forget that the hydraulic residence time of each CSTR is the overall residence time divided by n Second hint: this may require a numerical approach (e.g., Excel solver)