The gas-phase reaction A + B → C + D takes place isothermally at 300 K in a packed-bed reactor in which the feed is equal molar in A and B with CA0 = 0.1 mol/dm³. The reaction is second order in A and zero order in B. Currently, 50% conversion is achieved in a reactor with 100 kg of catalysts for a volumetric flow rate 100 dm3/min. The pressure-drop parameter, α, is α = 0.0099 kg^–1. If the activation energy is 10000 cal/mol, what is the specific reaction-rate constant at 400 K?