Charlotte E, 2011
Acids, Bases, and Indicators
Phenolphthalein is an indicator, which helps show whether or not an acid is affecting a base. Bases create hydroxide ions in water and acids create hydrogen ions in water. Together, these ions cancel each other out. If an indicator is present, the color changes as the base disappears and therefore indicates the change. Indicators are also put together to create the
Universal Indicator.


The Universal Indicator

The Universal Indicator measures the pH levels in an acid or a base. PH testing is away of measuring the strength in an acid or base. It measures the amount of compacted hydrogen or hydroxide ions within an acid or base and shows it by the color shown on the pH strip. The Universal Indicator measures pH levels zero to fourteen. Pink represents strong acids or bases at zero to two pH, green represents neutral strength with a six or seven pH level. A pH level of eleven and up means a strong base and is a dark purple.

Phenolphthalein is an indicator and acts like any other. It changes color when a base is neutralized by an acid. Phenolphthalein is also used in laxatives and making dyes.

  • Indicator- a chemical that reacts when acids and bases interact
  • Phenolphthalein- a type of indicator
  • Universal Indicator- many indicators put together to show pH levels in acids and bases

Newmark, Ann. Chemistry. London: Dorling Kindersley, 1993. Print.
Pasted from <>

Elements of Chemistry: Acids, Bases, and Salts. Prod. Discovery Education. Discovery Education, 2003. Discovery Education. Web. 30 September 2011.

"phe·nol·phthal·ein." American Heritage Student Science Dictionary (2009): 261. Science Reference Center. EBSCO. Web. 4 Oct. 2011.