The work carried out in this paper was specially designed to determine the efficiency of the imidazolium-based inhibitor to inhibit the corrosion of mild steel in a sulfuric acid solution. This was 1-Ethyl-3-methylimidazolium chloride [EMIM]Cl of which the concentration varied in 10-2, 10-3, 10-4, and 10-5 M and the solution was prepared with 0.5M H2SO4 and mild steel as the sample. From the results of the weight loss measurements, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and it also became clear that the performance of the steel increased in the presence of the inhibitor when immersed in various temperatures. Various Tafel plots prepared for the investigation unraveled the nature of ionic liquid that it was a mixed inhibitor inhibiting both anodic metal dissolution as well as cathodic events. In the EIS analysis, Inhibition efficiency was 94.51 % at the optimum concentration of 10-2 M. This was agreed by the results obtained from SEM and AFM imaging which provided evidence of the formation of a protective layer. It was however noted that the inhibition efficiencies were comparatively higher when the temperatures were low and this indicates that the formation of the inhibitive film is through the adsorption mechanism