A Definition and Explanation of pH

One method used to describe chemicals is pH or “potential of hydrogen”. A universally accepted scale for pH that describes chemicals as either “acidic” or “basic” is employed. This pH scale ranges from 0 to 14 with a pH of 7 being neutral; a pH less than 7 being acidic; and a pH greater than 7 being basic. For example, when the value begins at 7.0 and moves toward 0, acidity is indicated. When the pH moves from 7.0 toward 14, basic (alkalinity) is indicated. Hence, acids are divided from bases by this scale.

A useful category of solutions measured by the pH scale may be represented by:
…pH 0 to pH 2 is strongly acidic
…pH 3 to pH 5 is weakly acidic
…pH 6 to pH 8 is neutral
…pH 9 to pH 11 is weakly basic
…pH 12 to pH 14 is strongly basic.

pH values increase or decrease by a factor of ten when a change of one whole unit occurs. For example, a pH value of 4 is ten times more acidic than a pH value of 5 and 100 times more acidic than a pH of 6. (10x10). Likewise, a pH of 10 is 10 times more basic than a pH of 9.

Pure water is pH neutral but when mixed with chemicals , the solution formed may become either acidic or basic. Vinegar mixed with water will be acidic; washing detergents mixed with water will, generally, be basic.

Should chemicals be very basic or very acidic, severe harm may occur to the skin or to the eyes and caution must be exercised when handling such solutions.