The pH scale ranges from 0 to 14. On this simple scale, 0 is most acidic, 7 is neutral and 14 is the most alkaline. Litmus paper is commonly used to test the pH of a substance. Litmus paper is easy to use because it changes colour to indicate whether something is acidic or alkaline. However, litmus paper does have its limitations. You cannot get an exact pH measurement using litmus paper.
Pour the liquid or substance into a beaker or a glass. If you are working with a hazardous substance, make sure you are wearing goggles, an apron and gloves for protection.
Dip the litmus paper in the liquid. The litmus paper should be wet, but you do not need to soak it.
Compare the colour of the wet litmus paper to the colour chart that was included with the litmus paper. The colour chart provided by the litmus paper manufacturer will help you determine the pH of your substance.