Abstract: Based on the non - ideal Dusty - Gas Model (NDGM) and non - ideal Extended Stefan -Maxwell Model developed in the first part of this paper, and other models used widely for modeling the diffusion - reaction processes over a catalyst pellet, the effect of non - ideal characteristics of the reaction mixture on the predicted effectiveness factors of the catalyst is numerically studied for ammonia and methanol synthesis reactions. Parameter analysis of this effect has also been completed. The computation results and the comparison between the model prediction results and those observed show that non - ideal characteristics should be taken into account for those two reaction systems. NFICK is acceptable for ammonia synthesis reaction, but NESM or NDGM should be adopted for methanol synthesis from CO/CO2/ H2 gas mixture.