이유는 다음과 같습니다.
* Phenolphthalein is an indicator: This means it changes color depending on the pH of the solution.
* Acidic solutions have low pH: This means they have a high concentration of hydrogen ions (H+).
* Phenolphthalein is colorless in acidic solutions: The hydrogen ions in the acidic solution react with the phenolphthalein molecule, causing it to lose its pink color and become colorless.
In contrast, phenolphthalein turns pink in the presence of a base (alkaline solution).
