|MadSci Network: Chemistry|
An interesting question. The concise answer is no... it is not possible for an alkaline to have a pH of 15. However, I should point out a couple of things. First, a pH deals with solutions of acids or alkalines, not just an alkaline or an acid (because you can find both acids and bases in solid form). The pH is a measure of how the acid or base causes water to gain or lose a hydrogen atom (which is where the "H" in pH comes from). Acids cause the solution to have a lot of free hydrogen ions (hydronium ions, H3O+, which are hydrogen ions stuck onto a water molecule), and bases (alkalines) cause the solution to have a lot of free hydroxyl (OH-) ions. The limit to the pH scale is defined by an intrinsic constant of water's propensity to dissociate into hydronium and hydroxyl ions... which on the pH scale ranges from 0 to 14. So, you can't have a pH of 15. Hope this helps! Good Luck, J. Scott Miller
Try the links in the MadSci Library for more information on Chemistry.