What Is a pH Level?


The pH scale was developed to provide an easy way to describe how acidic or basic (alkaline) a solution is. Acids have a low pH, while bases have a high pH; pure water is neutral---neither acidic nor basic.


  • In 1909, the pH scale was proposed by the Danish scientist P. L. Sörenson. Up until then, describing the acidity of a solution was tedious and difficult.

Acids and Bases

  • An acid produces hydronium ions (H+) when dissolved in water, while a base produces hydroxide (OH-) ions when dissolved in water.

The pH Scale

  • The pH scale ranges from 1 to 14. Acids have a pH less than 7, while bases have a pH greater than 7.


  • Any time the pH of a solution is moved closer to 7, it is being neutralized. To raise pH, add a base; to lower pH, add an acid.

Litmus Paper

  • Litmus paper is used to obtain a crude measure of pH. Filter paper is treated with a dye that changes color, depending on pH; blue litmus paper turns red in an acid, and red litmus paper turns blue in a base.

pH Meters

  • For accurate pH measurements, a pH meter is better than pH test paper.

Related Searches


  • Fundamentals of Chemistry, 1994, David E. Goldberg, William C. Brown Publishers, Debuque, IA
Promoted By Zergnet



You May Also Like

Related Searches

Check It Out

How to Make a Vertical Clay Pot Garden

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!