We studied a kinetic model of a generic heterogeneous catalytic reaction 2A(*) + B-2(*) -> 2AB(g). This reaction includes the steps of adsorp tion and desorption of reactants A and B-2, where B-2 requires two neighboring adsorption sites to be adsorbed. We solved the model exactly and without any restriction on a 2 x 2 lattice. Despite the reduced number of sites employed, the solution shows the main general features observed by simulating the mechanism on a large N x N lattice. This result should encourage the search for an analytical solution as a reliable form to unravel details of a chemical reaction prior to performing numerical simulations. (c) 2007 Elsevier B.V. All rights reserved.