4. (25 pts.) The reaction 2A3R+S with rate rA=kCA2 where k=0.05L/ mole.s occurs in a steady-state PFR. The PFR operates under isothermal and isobaric conditions. Assume that g=1. The inlet contains reactant A and an inert species I at concentrations CA0=0.01 mole/ L and C10=4CA0. The concentration of A at the outlet is CAf=0.004 mole/L. Calculate the mean residence time, , and the Da parameter