The elementary irreversible aqueous phase reaction: A+B R+S is carried out isothermally as follows, Equal volumetric flow rates of two liquid streams are introduced into a 4 liter mixing tank. One stream contains 0.02 mol A/L, the other 1.4 mol B/L. The mixed stream is then passed through a 16 liter PFR. We find that some R is formed in the mixing tank, its concentration being 0.002 mol/L. Assuming that the mixing tank acts as a mixed reactor, find the concentration of R at the exit of PIR and conversion of A in the system.