A generalized Langmuir-Hinshelwood mechanism for the reaction A+1/2B_{2 ⇔} C has been studied. Lateral(nearest neighbor) interactions between the adsorbed species have been considered to analyze the multiple steady-states in the chemical reaction. Forward and reverse reaction rate constants have been evaluated via the lattice-gas model with the absolute rate theory. The simulation by the proposed model can predict multiple steady-states and hysteresis. Experimental correlation was made for the rate multiplicity observed by sung[3] on CO oxidation reaction.