Show that the steady-state exit concentration for a first-order reaction is \(1 /(1+D a)\). What is the corresponding expression if the reactor is modeled as a plug-flow reactor? Produce a comparison plot of the exit concentration for these two cases as a function of \(D a\). Show that if \(D a \lesssim 0.3\) then the mixing behavior is not important and the two models give nearly the same conversion.