Continuum and discrete models were combined for describe the solvent effects on the hydrogen bonded complex formed by ethylene oxide and hydrofluoric acid. In terms of continuum models, we applied the self-consistent reaction field polarized continuum model to verify the behavior of the C 2 H 4 O–HF heterocyclic hydrogen bonded complex in aqueous media in comparison to the gas phase by means of several parameters, such as intermolecular distance, Gibbs free energy and dipole moment. However, as widely known that continuum models are limited for describe adequately specific interactions between solute and solvent, the new AGOA methodology supply this hindrance by determining hydration clusters around the solute molecule. Based on the analysis of the molecular electrostatic potential of the solute (C 2 H 4 O–HF), the AGOA provided hydration clusters from optimized geometry using B3LYP/6-311++G(d,p) calculations. The result obtained justifies satisfactorily the acid catalyzed open ring reactions of the ethylene oxide because the preferential nucleophilic water attack occurs on the methyl groups of the three-membered ring, whose interaction energies values had reached up to −292.0kJmol −1 .