A.A. Siaka, N.O. Edd , S.O. Idris , L. Magaji , Experimental and Computational Study of Corrosion Potentials of Penicillin G, Research Journal of Applied Sciences, Volume 6,Issue 7, 2011, Pages 487-493, ISSN 1815-932x, rjasci.2011.487.493, (https://makhillpublications.co/view-article.php?doi=rjasci.2011.487.493) Abstract: Inhibition and adsorption potentials of penicillin G for the corrosion of mild steel in solutions of HCl have been investigated using experimental and quantum chemical approaches. The experimental study was carried out using gravimetric and Fourier transform infrared spectroscopy methods of monitoring corrosion while the quantum chemical study was carried out using quantum chemical approaches. The results obtained showed that various concentrations of penicillin G inhibited the corrosion of mild steel in solutions of HCl through the mechanism of physiosorption. The adsorption of penicillin G on mild steel surface was found to be exothermic and spontaneous and fitted the Langmuir Adsorption Model. DFT study has been used to identify the site for electrophillic and nucleophillic attack and the molecular orbital diagram of penicillin G has been drawn using Extended Huckel Method. Keywords: Inhibitor;potentials;corrosion;physiosorption and penicillin G;molecular