A combined experimental and theoretical approach to the study of hydrogen bond interaction in the binary mixture of N-methylimidazole with water

► Densities of N-methylimidazole with water binary mixture were measured. ► Excess molar volumes were fitted to Redlich-Kister polynomial equation. ► Excess molar volumes are negative in the whole mole fraction range. ► 1:1 Hydrogen complex formation between the unlike components was observed. ► Formation of hydrogen bonds in the binary mixture was confirmed by DFT//B3LYP.