A compound that changes color in the presence of an acid or a base
indicator
The compound you are referring to is known as an acid-base indicator or pH indicator. It is a substance that changes its color depending on the pH of the solution it is in. Some common examples of acid-base indicators include litmus paper, phenolphthalein, methyl orange, and bromothymol blue.
These indicators work by undergoing a chemical change when they come into contact with an acid or a base. For example, litmus paper turns red in the presence of an acid and blue in the presence of a base. This is because the acid or base changes the structure of the indicator molecule in a way that alters its absorption of light, resulting in a color change.
Acid-base indicators are commonly used in chemistry labs to determine the pH of a solution, or to monitor the progress of a chemical reaction. They are also used in everyday household items like swimming pool test strips, which use indicators to check the pH of the water.
More Answers:
The Importance of Understanding the pH Scale: Applications in Science, Biology, and Environmental StudiesUnderstanding the pH Scale: An Introduction to Acids and Bases
Understanding Universal Indicator Paper: A Reliable Qualitative Tool to Assess pH Levels in Chemistry Experimentations