In this work, the hydrodynamic behaviour in a partitioned bubble column is analyzed. Gas is introduced at the lower right corner and it rises through the liquid in the form of a plume. This induces a circulation in the liquid phase. The velocity field is predicted using CFD simulations based on an Euler-Eulerian (EE) approach and validated experimentally using Ply. Mixing between the liquids in the two halves of the tank is studied by analyzing the progress of the fast neutralization reaction between HCl and NaOH. It is found that mixing is slowed down when the higher viscosity fluid is present in the half containing the gas source. This is understood by analyzing the velocity fields using Ply. It is shown that mixing can be controlled by changing the gas flow-rate. A consecutive-competitive reaction is studied and the effect of mixing on selectivity is analyzed. (C) 2012 Elsevier B.V. All rights reserved.