pH Scale
The pH scale is used to measure the acidity or alkalinity of a solution. The pH scale ranges from 0 to 14. A pH of 7 indicates a neutral state in which the H+ and OH- ions are equal. A pH below 7 is acidic and a pH greater than 7 is basic, or alkaline. For every number you move up the scale (or down) the difference is 10 times greater. So a pH of 3 is ten times more acidic than a pH of 4. A pH of 11 is one hundred times more basic than pH 9.
Below, you can see where several common items range on the pH scale.
Below, you can see where several common items range on the pH scale.