This study investigates the role of charge in microdroplet redox chemistry, focusing on how the thermodynamics of electron transfer processes are influenced by the charge state of water microdroplets. The research demonstrates that when microdroplets reach approximately 20-50% of the Rayleigh limit (the maximum charge they can stably hold), the hydration enthalpies of hydroxide (OH⁻) and hydrogen (H⁺) ions decrease significantly, making electron transfer thermodynamically favorable. This is supported by changes in vertical ionization energy (VIE) and vertical electron affinity (VEA) of the ions, which further enhance the reactivity of radicals such as OH· and H·. The findings suggest that the charge on microdroplets plays a crucial role in enabling redox reactions, particularly the formation of hydrogen peroxide (H₂O₂), which is thermodynamically unfavorable in bulk water. The study also shows that the observed effects at the nanoscale can be scaled up to microdroplet systems, indicating that the charge-induced changes in reaction thermodynamics are relevant to experimental observations. The research provides a theoretical basis for the accelerated redox chemistry seen in microdroplets and highlights the importance of charge in modulating chemical reactivity in these systems. The results have implications for understanding and predicting redox reactions in microdroplets generated through processes like sonication and electrospray.This study investigates the role of charge in microdroplet redox chemistry, focusing on how the thermodynamics of electron transfer processes are influenced by the charge state of water microdroplets. The research demonstrates that when microdroplets reach approximately 20-50% of the Rayleigh limit (the maximum charge they can stably hold), the hydration enthalpies of hydroxide (OH⁻) and hydrogen (H⁺) ions decrease significantly, making electron transfer thermodynamically favorable. This is supported by changes in vertical ionization energy (VIE) and vertical electron affinity (VEA) of the ions, which further enhance the reactivity of radicals such as OH· and H·. The findings suggest that the charge on microdroplets plays a crucial role in enabling redox reactions, particularly the formation of hydrogen peroxide (H₂O₂), which is thermodynamically unfavorable in bulk water. The study also shows that the observed effects at the nanoscale can be scaled up to microdroplet systems, indicating that the charge-induced changes in reaction thermodynamics are relevant to experimental observations. The research provides a theoretical basis for the accelerated redox chemistry seen in microdroplets and highlights the importance of charge in modulating chemical reactivity in these systems. The results have implications for understanding and predicting redox reactions in microdroplets generated through processes like sonication and electrospray.