The residence time distribution, $E$, for a non-ideal flow reactor is given in the figure. A first-order liquid phase reaction with a rate constant $0.2 \mathrm{~min}^{-1}$ is carried out in the reactor. For an inlet reactant concentration of $2 \mathrm{~mol} \mathrm{~L}^{-1}$, the reactant concentration (in $\mathrm{mol} \mathrm{L}^{-1}$ ) in the exit stream is
- $0.905$
- $0.452$
- $1.902$
- $0.502$