This study investigates the dynamic interactions of hydrodynamics, mass transfer and reaction in a bubble column reactor by means of numerical simulation and experimental observation. The model reactor was operated in the homogeneous flow regime. The chemisorption of carbon dioxide in sodium hydroxide was chosen as a fast model reaction. As a consequence of the enhanced mass transfer, bubble sizes and gas holdup decrease significantly in the axial direction. A one-dimensional, dynamic model was developed in order to predict the transient behaviour of the reaction system in the bubble column. The change of the bubble size due to carbon dioxide consumption has been incorporated by means of a population balance equation. This allows for the prediction of local time-dependent values of gas holdup and of the interfacial area. The numerical simulation was compared with experimental results. A good quantitative agreement was obtained.