b) A first-order heterogeneous irreversible reaction is taking place within a spherical catalyst pellet with diameter of 0.15 cm. The reaction is performed in a packed bed reactor with a diameter of 60cm which is working at steady state. The catalyst density is 2.3 g.cm³ and the bed porosity is 0.28. The gas phase diffusivity and effective diffusivity of A are 0.75 x 101 cm².s¹ and 0.5 cm².s', respectively. The kinematic viscosity of A is 0.02 cm2.s. The volumetric flowrate to the reactor is 50,000 cm³.s and the reaction rate constant is 10 (cm³.gl cat. s¹). The inlet concentration of A into the reactor is 8.5x102 mol.cm³. Assume isothermal operation and the pressure drop across the reactor is negligible, i) Evaluate whether the reaction is limited by mass transfer or surface reaction. (20 Marks) ii) Estimate the weight of catalyst needed for 85% conversion of A. (10 Marks)