6-1. The RTD for a reactor is to be determined by tracer-concentration measurements. With a constant-density isothennaI system, the following effluent concentration data are obtained in response to a pulse of tracer added to the feed: [,min Tracer concentration, g/cm3 o 5 o 3.0 10 15 5.0 5.0 20 25 30 35 4.0 2.0 1.0 o (a) Plot both J(B) and f(B) vs time on the same figure. (b) What is the mean residence time for the flow rate used?