Phenolphthalein

Definition

Phenolphthalein is a chemical compound often used as an indicator in titrations. It is colorless in acidic solutions and turns pink in basic solutions.

Analogy

Think of phenolphthalein like a traffic light for chemists. Just like how a traffic light changes color to signal drivers when to stop or go, phenolphthalein changes color to tell chemists when the reaction has reached its endpoint.

Related terms

Acid-Base Indicator: A substance that changes color depending on the pH of the solution it's in. Phenolphthalein is one type of acid-base indicator, just like how a traffic light is one type of road signal.

pH Scale: A measure of acidity or alkalinity of water soluble substances. It's like our "road map" that tells us what color our "traffic light" (phenolphthalein) should be.

Alkaline Solution (Basic Solution): A solution with a pH greater than 7. When phenolphthalein enters this territory, it turns pink - just like how a traffic light turns red to signal drivers to stop!