Toxicity factors affecting

According to reports in the hterature, the degree of toxicity of a poison molecule is related to two factors. One is coverage-factor (s), which refers to the number of atoms or groups of active sites on the catalyst covered by the atoms or molecules of adsorbed poison. The other is life-factor (t) of adsorption, which refers to the average residence time of the molecules of poison on the catalyst surface. 

Thus the effective toxicity of poison can be expressed as a function of these two factors  

The factor (s) relates to the nature and structure of the toxic elements, and the effective volume of the moving at space for the poison the life-factor t) of adsorption depends largely on the nature of the toxic elements and their molecular structure. As the life-adsorption of poison is much longer than that of the reactant molecule, so even a very low concentration of poison still can inhibit the adsorption of the reactant molecule and lead to the catalyst losing its activity as the poison accmnulates on the catalyst s surface. 

24 The competitive adsorption between sulfur and nitrogen atoms on Pe (111) face 

As a result, increasing the temperature, pressure and concentration of poison, as well as a protracted contact time of catalysts with a poison, will aggravate and continue the redox process, heightening the tendency of permanent poisoning. 

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In which two ways can genetic factors affect toxicity. Give an example of each. 

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