Complete knowledge of the pressure field distribution in a sonochemical reactor should be known for an efficient utilization of acoustic energy emitted by the transducers for targeted physicochemical transformations using cavitation phenomena. This work deals with the identification of the active and passive regions in the sonochemical reactor based on the measured pressure field intensities. Iodine liberation experiments based on the decomposition of aqueous potassium iodide (KI) as a representative of cavitationally induced chemical transformation were carried out at various locations in the bath type reactor and compared with the measured pressure intensities in the reactor. Similarly, extraction of natural dye from the bark of Pterocarpus marsupium tree has also been carried out as a representative of cavitationally induced physical transformation (extraction) and compared with the measured pressure intensities. Both the transformations indicate a similar trend of variation in the degree of transformation when correlated with the local pressure and indicated the existence of an optima, which is at a plane (≈3λ/2) away from the transducer surface.