In this work, physics of complex gas-liquid flow in bubble column reactor where the interactions are not well understood is investigated experimentally using Particle Image Velcoimetry (PIV) and computationally through Euler-Eulerian & Euler-Lagrangian CFD simulations. Further, (i) multiple reaction (consecutive - competitive) (ii) acid -base mixing (iii) uric acid electrolysis and (iv) effect of surfactant on hydrodynamics of gas-liquid flow in bubble column reactor is investigated.