A first-order homogeneous liquid-phase reaction ( $\mathrm{A} \rightarrow \mathrm{B}$ ) occurs in a non-ideal isothermal reactor operating at steady state. The variance ( $\sigma^{2}$ ) of residence time distribution (RTD) from a pulse tracer experiment is $4 \mathrm{~min}^{2}$. The volumetric flow rate of the feed is $5 \mathrm{~L} \mathrm{~min}^{-1}$ and volume of the reactor is $25 \mathrm{~L}.$ The reaction rate constant is $0.4 \mathrm{~min}^{-1}$. Based on the tanks-in-series model, the conversion (in $\%$) is $\_\_\_\_$ (rounded off to one decimal place).
