A neutral solution has a pH of 7.0. Smaller numbers are acidic and numbers larger than 7 represent base solutions. For example, a solution with a pH of 3 would be an acid. Another solution with a pH of 9.5 would be alkaline. Litmus paper is often used to give a rough estimate of the pH. When the paper turns red, the material is acidic, and when the paper turns blue, it contains a base.
Gardeners use the pH scale to determine how acidic or alkaline their soil is.
The pH scale is also used to help determine water quality. Salts Salts are important for sustaining life because they provide minerals to the body. Salts are formed by the chemical reaction of an acid and a base, in water. Since salts are more stable than either acids or bases, you will find more of them in nature. Bases are also caustic and cut grease.