Abstract We studied a kinetic model of a generic heterogeneous catalytic reaction 2 A ∗ + B 2 ∗ → 2 AB g . This reaction includes the steps of adsorption 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 × 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 × 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.