Theoretical properties of breakthrough curves (BTCs) of solutes subject to nonlinear sorption, precipitation/dissolution and homogeneous reactions are compared with numerical simulations. The example treated here involves heterovalent ion exchange on clays, ionization of carbonic acid and water, and dissolution of gaseous carbon dioxide and of solid calcite. Despite the complexity of the solid-fluid interaction mechanism (13 reacting species and six reactions), the number of waves, the possible existence of an unretarded wave, and the expressions for the concentrations of the stoichiometric tracers are easily derived from the stoichiometric matrix. The location of peaks or waves and their broadening characteristics due to the nonlinear equilibria are estimated exclusively from the compositions of the injected and initial solutions. All of these theoretical properties are confirmed by numerical simulations, even in the presence of dispersion. The number of waves and the stoichiometric tracers are shown to depend on whether or not the pore solution equilibrates with a gas phase. This property illustrates the strong sensitivity of the breakthrough curves to the interaction mechanism. Finally, calculating the BTCs of the stoichiometric tracers from the experimental BTCs of the liquid phase species allows one to discriminate among rival interaction mechanisms without requiring a numerical model and knowledge of the equilibrium constants. ¿ American Geophysical Union 1993