Consider the production of $1,1-$dichloroethane $($C$2$H$4$Cl$2)$ from ethylene $($C$2$H$4)$ and chlorine $($Cl$2).$ Reaction is given below. This gas$-$phase reaction is the first step in polyvinyl chloride $($PVC$).$ The feed ratio of reactants is $2$ moles chlorine: $1$ mol ethylene. You may assume $$hrxn does not change with temperature. Calculate the maximum temperature at which $90\%$ conversion can be obtained at a pressure of $1$ bar.

C$2$H$4($g$)+$ Cl$2($g$)$ C$2$H$4$Cl$2($g$)$