4. The anionic solution polymerization of styrene can be used to produce "living" polystyrene polymer. Assume an initial styrene monomer concentration of [M] = 4.62 x 10-1 mol/L and initiator concentration of [I] = 4.8 x 10-4 mol/L in a solvent solution. (a) Based on the rate of propagation constants, kp, from the table below, if the monomer concentration in the reactor is depleted by 99.9% after 3.0 min, determine what type of initiator counterion and solvent (tetrahydrofuran or dioxane) combination was used for this reaction. (b) With disruptions in the market, the unit cost of initiator becomes the same amount for all of the counterion packages listed below. Your boss has asked you to come up with an initiator/solvent combination that will match the same performance characteristics in terms of monomer consumption rate as the case above (99.9% monomer consumption after 3.0 min) but at a lower initiator cost per production cycle. Calculate which combination of solvent and minimum value for initiator concentration you can get by with in order to match the specified monomer consumption rate. (c) Based on your solution from part (b) above, what is the net impact on Mn for the polystyrene polymer produced? (d) Based on your solution from part (b) above, how would you change your initial styrene monomer concentration in order to match your original Mn value? Counterion Li+ Na+ K+ Rb+ CS+ for dioxane kp (L/ (mol s)] 0.94 3.4 19.8 21.5 24.5 for tetrahydrofuran kp [L/ (mol s)] 160 80 60 50 22