Okay, if you want to get perfectly accurate;
pH is a measure of the hydorgen ion concentration of a solution. Solutions with a high concentration of hydrogen ions have a low pH and solutions with a low concentrations of H+ ions have a high pH. This may seem like a confusion way to express these reationships, and it is, until you understand what pH stands for. The equation that defines pH is given as follows:
pH=-log[H+] concentration,
which is read:
the pH is equal to minus the log of the H+ concentration.
For example is the H+ concentration is very low, lets say about 0.0000001M, then the pH is
pH= -log[.0000001] whis is the same as -log[1 X 10-7]
the term log[1 X 10-7] = -7
- (-7) = 7
You add salt and it's mineralization and the equation gets even more complicated. It comes down to ionic balances.
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