This is certainly NOT a homework assignment. I am a medical student and we are learning about oral flora, I read that the safe zone for enamel is a pH of 5.5, and as a diet soda drinker I am curious if this is even possible. I probably should remember how to do something like this. The ph of most sodas are between 2.5-4.7. I'm taking the extreme end of 2.5. How much water would I have to add to raise the solution up to a ph of 5.5. The ingredients of diet coke is: Carbonated water, caramel E150d, sweeteners (spertame), flavoring (caffeine), phsophoric acid, citric acid. I got this off the UK coke site but it should work well enough. I assume that the phosphoric acid and citric acid are what drop the pH. Both are weak acids, correct? I'm sure I could probably look up an example of this, but I'm not sure I could find one that uses a solution like this. Is there any way to calculate this based on the pH of a solution, rather than the pka of some particular component. Any help would be appreciated.