Investigations indicate that both tolyltriazole (TTA) and benzotriazole are strongly adsorbed on iron in sulfuric acid solution. The former is a more effective corrosion inhibitor at low concentrations, possibly as a consequence of the larger surface area covered by the adsorbed molecule. The corrosion rate of iron decreases with increasing concentration of TTA till a limiting value is reached. Similar effectiveness is displayed by both inhibitors at higher concentrations. An increase in pH also favors inhibition. -- AATA