4. For the reaction A -> products, which takes place in the liquid phase, the reaction rate dependence on the concentration of A is presented in the following figure. For a feed stream with Qo = 5 lt/s and CAo = 15 mol/lt, find the reactor system with the lowest possible total volume and find the volume of the reactors when the desired concentration of A at the exit is: (a) 10 mol/lt, (b) 5 mol/lt and (c) 2 mol/lt.