Substances that change color when added to an acidic or a basic solution are called indicators. Litmus is a natural indicator. When litmus is used to determine whether a substance is an acid or a base, it is called a litmus test. Litmus is also available in the form of paper strips, known as litmus papers. Litmus paper comes in two colors: red and blue. Blue litmus paper turns red in an acidic solution, and red litmus paper turns blue in a basic solution.
After completing this module, you will be able to:
- Define the term indicator.
- Explain litmus as an indicator.
- Demonstrate litmus tests for acidic, basic, and neutral solutions.
- Predict the nature of various solutions on the basis of litmus test.