Homonym: litmus (Test)
Litmus is a natural dye derived from certain species of lichens, primarily found in the genus Roccella. It is commonly used as a pH indicator, changing color in response to the acidity or alkalinity of a solution. When added to an acidic solution, litmus turns red, while in alkaline conditions, it turns blue. This property makes it a useful tool in chemistry for determining the pH level of various substances.
In addition to its use in laboratories, litmus paper is widely available and used in educational settings to teach students about acids and bases. The simplicity and effectiveness of litmus as a pH indicator have made it a staple in both scientific research and everyday applications.