Problem 3: 20 points The gas-phase hydrodesulfurization of thiophene C4H4S+4H2C4H10+H2S was studied at 523K and 1atm total pressure using a Co-Mo catalyst. In all experiments, H2 was in excess over thiophene. The reactor used was essentially a CSTR. In one steady-state experiment, a reaction rate of 6.13106molC4H4S/g cat. min was measured. The reaction rate constant was calculated to be 3.54cm3/g cat. min (Note: this value can be converted to units of [time] 1 by multiplication with the particle density). The catalyst particles were spheres of diameter of 0.277cm. The BET surface area of the catalyst was 343m2/g; the specific pore volume was 0.470cm3/g; and the particle density was 1.17g/cm3. The bulk molecular diffusivity of C4H4S/H2 at reaction conditions is 1.01cm2/s. (a) Estimate the mean pore radius for the catalyst. (b) What is the Knudsen diffusion coefficient of thiophene? (c) What is the effective diffusion coefficient of thiophene? (Since no value was reported for the tortuosity, a typical value =4.0 can be used). (d) If the reaction is first-order in thiophene, and if there is no significant external masstransport resistance, what is the value of the effectiveness factor