Litmus paper is a type of pH indicator, meaning it changes color depending on the acidity or alkalinity (basicity) of a solution. It's made from a mixture of lichen dyes, and its color change is a result of the chemical reaction between the dyes and the hydrogen ions (H+) in acidic solutions or hydroxide ions (OH-) in alkaline solutions.
Here's a breakdown:
* Acidic solution: Litmus paper turns red in the presence of excess hydrogen ions (H+).
* Alkaline (basic) solution: Litmus paper turns blue in the presence of excess hydroxide ions (OH-).
* Neutral solution: Litmus paper stays purple in a neutral solution, where the concentration of H+ and OH- ions are equal.
