List of top Chemical Reaction Engineering Questions on Diffusion effects in catalysis asked in GATE CH

An irreversible chemical reaction occurs on a porous catalyst. All the pores are of same size. In strong pore diffusion regime, the observed activation energy is 120 kJ mol^-1. The activation energy of diffusion is 10 kJ mol^-1. Assuming Arrhenius temperature dependency for both reaction and diffusion, which one of the following is the true activation energy (in kJ mol^-1) of the reaction?

A first-order heterogeneous reaction \( A \rightarrow B \) is conducted using a porous spherical catalyst under isothermal conditions, where intraphase diffusion governs the reaction rate. At a bulk A concentration of 0.3 mol L\(^{-1}\), the observed reaction rate in a 3 mm diameter catalyst particle is 0.2 mol s\(^{-1}\) L\(^{-1}\) catalyst volume. At a bulk A concentration of 0.1 mol L\(^{-1}\), the observed reaction rate in a 6 mm diameter catalyst particle, in mol s\(^{-1}\) L\(^{-1}\) catalyst volume, is:

CO and H\(_2\) participate in a catalytic reaction. The partial pressures (in atm) of the reacting species CO and H\(_2\) in the feed stream are \(p_{CO}\) and \(p_{H_2}\), respectively. While CO undergoes molecular adsorption, H\(_2\) adsorbs via dissociative adsorption (as H atoms). The equilibrium constants (in atm\(^{-1}\)) corresponding to adsorption of CO and H\(_2\) to the catalyst sites are \(K_{CO}\) and \(K_{H_2}\), respectively. Total molar concentration of active sites per unit mass of the catalyst is \(C_t\) (in mol\(\cdot\)(g cat)\(^{-1}\)). Both the adsorption steps are at equilibrium. Which one of the following expressions is the CORRECT ratio of the concentration of catalyst sites occupied by CO to that by hydrogen atoms?

The reaction A → B is carried out isothermally on a porous catalyst. The intrinsic reaction rate is $k C_A^2$, where $k$ is the rate constant and $C_A$ is the concentration of A. If the reaction is strongly pore-diffusion controlled, the observed order of the reaction is