What reaction schemes and conditions would you use to maximize the ' selectivity parameters S for the following parallel reactions: where D is the desired product and U1 is the undesired product? (b) State how your answer to part (a) would change if C were to react with D to form another undesired product. At what temperature should the reactor be operated if the concentrations ofA and D in the reactor were each 1 mol/dm3? (c) For a 2-dm3 laboratory CSTR with Cco,= CAo= 1 mol/dm3 and vo = 1 dm3/min, what temperature would you recommend to maximize YD'? (d) Two pas-phase reactions are occurring in a plug-flow tubular reactor, which is operated isothermally at a temperature of 440°F and a pressure of 5 atm. The first reaction is first-order: