What color does phenolphthalein turn in an alkali?

Phenolphthalein is a pH indicator commonly used in titrations and various chemical experiments. In an alkaline (basic) environment, phenolphthalein exhibits a noticeable color change. Specifically, it turns pink when the pH is above approximately 8.2. This pink coloration occurs because the phenolphthalein molecule loses protons (H⁺ ions) in a basic solution, leading to a structural change that results in the vibrant pink hue.

In contrast, in acidic conditions, phenolphthalein remains colorless, which can sometimes lead to confusion when interpreting results if not aware of this property. In neutral conditions, it may also appear colorless. However, the defining characteristic of phenolphthalein is its pink color in alkaline solutions, making this answer the most accurate representation of its behavior in different pH environments.