The possible existence of multiplicity features, including ignition and extinction phenomena, is theoretically examined for ethylene hydrogenation in the kinetic region with the exclusion of heat and mass transfer limitations, and then the ethylene hydrogenation is compared with CO oxidation for which it has been claimed in several studies that multiple steady states can come from a purely kinetic process. From both theoretical and numerical analyses, it is concluded that if each chemisorbed ethylene occupies less than two active sites of catalyst more strongly than hydrogen the multiple steady states can exist, but the multiplicity features can not be obtained if an ethylene molecule adsorbs strongly upon more than two active sites. From our experiment and another studies for chemisorptions, it is confirmed that the chemisorption of ethylene requires geometrically 3-4 active sites per each molecule and that is much more strong than one of hydrogen. Therefore, the existence of kinetically induced multiplicity will not be possible for ethylene hydrogenation. On the other hand, the kinetically induced multiplicity for CO oxidation will arise from the fact that carbon monoxide chemisorbs more strongly than oxygen upon less than two active sites. In our study, it is found that the number of geometrically occupied active sites rater than the chemical bonding number in the chemical bonding number in the chemisorption of reactants might exert an important influence on the existence of the multiplicity features in the reaction proceeding via Langmuir-Hinshelwood mechanism.