[updated:LAST EDITED ON Nov-11-08 AT 09:22 AM (CDT)]Hi: As far as I have read in books, redox reaction in oxidizing acid are of such a high (positive) potentials that they can easily oxidize most metals such as steel. One of the most powerful oxidizing acids is Nitric acid which its redox reaction potential is as high as 1.3 V, so it readily oxidizes steel. On the other hand there are non-oxidizing acids such as Hydrochloric acid and Sulfuric acid which are reluctant to give up their oxygens to the metal. Although they reduce the pH of the solution considerably, they can't oxidize the metal. This is why we use anodic protection to protect steel in Sulfuric acid. Finally, nonoxidizing acid can turn oxidizing by incorporation of air into them or contamination with oxidizing ions such as ferric iron. Best Wishes