Cars have catalytic converters fitted to their exhaust pipes. The catalytic converters are made from a honeycomb of ceramic material coated with the metallic catalysts platinum, palladium or rhodium. The honeycomb provides a large surface area for the reactions:carbon monoxide + nitrogen oxides → carbon dioxide + nitrogenhydrocarbons + nitrogen oxides → nitrogen + carbon dioxide + waterThe reactants are adsorbed onto the surface of the catalyst.Bonds within the reactants break.New bonds form between the reactants.The products desorb from the surface of the catalyst.