After 1000 s of exposure of AZ31-4Li, AZ31-8Li, and AZ31-12Li to the 0.05 M NaCl solution without the inhibitor, the pH values increased to 7.2, 7.7, and 9.2, respectively (Fig. ). The introduction of Na2MoO4 into the 0.05 M NaCl solution increased the initial pH of the solution. This is due to the molybdic acid is a weak acid (pKa = 6) and its salts are hydrolyzed in aqueous solutions. In the presence of 10 and 50 mM of the molybdate inhibitor, pH values were rapidly increasing, suggesting activation of the corrosion process in time. In turn, at higher concentrations of the molybdate in the solution pH remained quite stable in time, which is a sign of improved corrosion resistance and retardation of the corrosion process.