Abstract: An acid molten salt was formed by means of mixing 1-methyl-3-ethylimidazolium chloride with AlCl₃ and LiAlCl₄ at ambient temperature. The solubility of LiAlCl₄ in the acid molten salt was measured. Variations of specific conductivity, density and kinetic viscosity of molten salt with mole ratio of MeEtlmCl/AlCl₃/LiAlCl₄ were observed. A solubility maximum of LiAlCl₄ with 54% in molar fraction was shown at a mole ratio of AlCl₃/MeEtlmCl = 1.2. An increase in density and viscosity, and a decrease in specific conductivity were found with increasing the concentrations of LiAlCl₄ and AlCl₃. The dependence of specific conductivity of this acid molten salt upon temperature was found to display Vogel-Tammanm-Fucher behavior. However, Arrhenius behavior was observed at two special mole ratios of MeEtImCl/AlCl₃/LiAlCl₄ = 1:1.5:0.05 and 1. 1.5:0. 10. The conductivity equations of this molten salt at various compositions were constructed. The ion interaction in the acid molten salt was studied using ⁷Li and ²⁷Al nuclear magnetic resonance spectroscopic methods. The effect of concentrations of LiAlCl₄ and AlCl₃ on the ion interaction was also discussed.