Steady state multiplicity features of systems in which two reactions occur simultaneously may be affected by thermal and kinetic interactions and be qualitatively different from those of a single reaction. This is illustrated by an experimental study of the catalytic co-oxidation of hydrogen with either ammonia, butane or ethylene on a Pt wire. The bifurcation diagrams of wire temperature at a fixed hydrogen concentration vs. co-reactant concentration reveal multiplicity features which cannot be accounted for just by thermal interaction. The ignited branch was discontinuous at intermediate H2 concentrations and extinction occurred upon increasing the co-reactant concentration. The loci of the observed ignition and extinction points were used to construct a bifurcation map in the concentration plane. The maps show that kinetic inhibition exists between the two reactions in addition to thermal interaction.