4) a) The rate constant of a reaction is given as k= 30 mg. L'h'. Based on the units of k determine the order of the reaction. (5 points) b) A completely mixed flow reactor treats wastewater from a small facility. The relevant reaction follows second-order kinetics, with k=0.01 L.mg'h'. The reactor volume is 500 m, and the inlet pollutant concentration is 60 mg/1. What should be the flow rate for 95% of the waste to be removed? (25 points)