In order to analyze the dynamics that control bimolecular reactive transport, we study the irreversible chemical reaction A + B → C. We use a reactive random walk particle tracking (RWPT) pore scale model capable of simulating bimolecular reactive transport. We focus on the experimental scenario reported by Jiménez-Martı́nez et al. (2015) to determine the impact of flow heterogeneities on the irreversible reaction. These authors studied the conservative displacement B by A in a 2-dimensional porous medium characterized by a random grain packing. We determine the corresponding experimental reactivity based on the concentration data for the invading fluid. We quantitatively account for the total mass of product C (m_C (t)) and the mixing zone between the reactants from the laboratory experiment. Then, we simulate transport and reaction in the image of the experiment’s geometry to validate the reactive RWPT model through predicting the experimental results. Our model accurately predicts the evolution of m_C (t) in the experiment as it captures the degree of incomplete mixing present at the pore scale. Our results are in contrast to the advection-dispersion-reaction equation model that overpredicts m_C (t) in the medium because assumes complete pore scale mixing.