$($b$)$ For the isothermal, isobaric gas$-$phase pyrolysis

$C_2{H}_6{C}_2{H}_4+H_2$

pure ethane enters the flow reactor at $6$atm and $1100K.$ How would your equation for the concentration and reaction rate change if the reaction were to be carried out in a constant$-$volume batch reactor?

$($c$)$ For the isothermal, isobaric, catalytic gas$-$phase oxidation ${?}^{C_i}=C_{A_0}\frac{{}_i+\frac{{}_i}{a}x}{1+x}$

$C_2{H}_4+\frac{1}{2}{O}_2{C}_2{H}_{4}O$

The feed enters a PBR at $6$ atm and $260C$ and is a stoichiometric mixture of oonly oxygen and ethylene.

From $($b$)$ why the epsilon for batch reactor is $0?$