3. Consider an irreversible second-order reaction, 2AB (with rate, rA=kCA2 ) that has been carried out in a batch reactor. The initial concentration is 1mol/liter, and after 30 minutes the concentration is 0.25mol/ liter. a) What is the value of the second-order rate constant? Show units. (10 points) b) If the reaction is to be conducted in a plug flow reactor, with a feed concentration of 1 mol/ liter and a flowrate of 2 liters/minute. To achieve an outlet concentration of 0.25mol/ iter, what should be the volume of the PFR