Acidifying the mixture with concentrated sulphuric acid during the synthesis of aluminium/potassium nanoparticles (Pl-Al/KNPs) induced a colour change from dark brown to light brown indicating successful nanoparticle formation. This change results from the Surface Plasmon Resonance (SPR) phenomenon, where conduction electrons on the nanoparticle surface resonate with incident light, confirming the presence of nanoscale particles . Electrostatic interactions and hydrogen bonding between the capping and stabilizing agents in the rice straw extract and aluminium ions also drive the synthesis process. These interactions are essential for reducing aluminium ions to nanoparticles and preventing their agglomeration by stabilizing them in the solution. The transition from dark brown to light brown during synthesis is consistent with literature findings, suggesting the reduction process completes within 24 hours. . P.