Defining the Litmus Test
A litmus test is a quick and simple chemical test used to determine if a solution is acidic or basic (alkaline). It uses a special paper called litmus paper, which is paper treated with a specific dye extracted from lichens.
Section 2: How Litmus Paper Works
The dye on the litmus paper is a pH indicator, meaning it changes color when it comes into contact with solutions of different pH levels. There are two common types of litmus paper: red and blue. Each one is designed to react to either an acid or a base.
Section 3: A Practical Example: Interpreting Results
To test an unknown liquid like lemon juice, you would dip a strip of blue litmus paper into it. Because lemon juice is acidic, the blue paper will instantly turn red. Conversely, if you dip red litmus paper into a basic solution like soapy water, it will turn blue. If there is no color change, the solution is likely neutral.
Section 4: Importance and Applications
The litmus test is a fundamental tool in school science labs and various industries for a quick, qualitative assessment of a substance's pH. While not as precise as a pH meter, it provides an immediate visual confirmation of whether a substance is an acid or a base, which is crucial for safety, classification, and further experiments.