The paper addresses the steady-state behavior of a reactive flash, characterized by an exothermic isomerization reaction with first-order kinetics and a light-boiling reactant. The dimensionless model distinguishes between the state variables, control parameters, and system properties. The combination of state multiplicity and feasibility boundaries corresponding to no-liquid or no-vapor products leads to complex steady-state behavior. Twenty-five bifurcation diagrams are presented, exhibiting a maximum of three steady states and five feasibility boundaries. Singularity theory is used to divide the Damkohler number-heat input space into regions with qualitatively different behavior for liquid, vapor, and vapor-liquid feeds. Further, it is shown that large heat of reaction, activation energy, and reactant volatility enlarge the range of operating parameters for which multiple states exist.