Re: is it possible for an alkaline to have a pH of 15?

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