The value of pH is the negative log of the hydrogen ion concentration in moles per liter.
A solution with a pH of 6 is 1000 times more acidic than a solution with a pH of 9
Stomach Acid= 2 Blood= 7.4 Acid Rain= 1.5-5.4
The internal pH of most living cells is close to 7, pH is regulated by buffers which are substances that resist a change in pH. The most important buffer in human blood is the bicarbonate ion