Answer the following question given this paragraph: An acid-base indicator is a substance that displays different colors when in the presence of an acid or a base. How does that work? An indicator is a weak acid that ionizes within a known pH range, usually about 2 pH units. We can represent the protonated form of the indicator molecule as HIn and the deprotonated form as In . The following equilibrium exists for the indicator. Q: A substance that displays different colors when in the presence of an acid or a base is called what? Choices: - pH scale - reactor - litmus test - an acid-base indicator A:
The answer to this question is:
an acid-base indicator