Journal of African Development

The rate of a chemical reaction is governed by the combined influence of the intrinsic properties of reactants and the physicochemical characteristics of the solvent. Quantitative and qualitative relationships between these factors can be described using several classical and modern kinetic equations that provide insight into reaction mechanisms, transition-state stabilization, and solvent–solute interactions. This review summarizes the principal equations employed to evaluate the effects of reactant and solvent parameters on reaction rates, including the Arrhenius equation, Eyring transition-state equation, Hammett equation, Taft equation, Brønsted relationship, Hughes–Ingold theory, Grunwald–Winstein equation, Kirkwood equation, and Linear Solvation Energy Relationships (LSER). These models relate reaction kinetics to activation energy, substituent electronic effects, steric influences, solvent polarity, dielectric constant, nucleophilicity, ionizing power, and hydrogen-bonding ability. The review highlights how these equations complement one another in explaining kinetic behavior across aqueous, non-aqueous, and mixed solvent systems. Particular emphasis is placed on solvent-induced changes in activation parameters, transition-state stabilization, and structure–reactivity correlations. The comparative analysis demonstrates that no single equation completely describes all kinetic phenomena; rather, a combination of mechanistic and empirical relationships provides the most reliable prediction of reaction rates. The study serves as a comprehensive reference for researchers investigating chemical kinetics, physical organic chemistry, and solvent effects, while offering practical guidance for selecting appropriate kinetic models to interpret experimental rate data and predict reaction behavior under varying reaction conditions...