Dear PF Forum, Actually I want to study how antioxidant can benefit for our health. But, my understanding in chemistry is very limited. Perhaps I have to go back and study pH, first. I have read many sources in the internet. And this is one of them: http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/what-is-pH.shtml So, let me understand this first. 1. In 1 liter of water, there are approximately 1000/18.016 (weight of H2O, including isotope) = 55.51 moles of H2O. Is it true? 2. For 1 liter water which have pH = 0 (if this is chemically possible) there are 1 moles H+ about 1 .008 gram? 2. In 1 liter water pH = 1, there are 1/10 moles or 0.1 gram H+? 3. Neutral water, pH = 7, there are 1 x 10-7 moles H+ or about 0.1 microgram H+? 4. If number 3 is true. Why is it neutral? Because there are 1.7 microgram Hydroxide as well? Thanks for helping me. I might have some questions more to ask.