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Acid-Base Indicators definitions

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  • Acid-Base Indicator
    A weak acid or base that changes color at a specific pH during titration to signal the endpoint.
  • Endpoint
    The point in titration just after the equivalence point where the indicator changes color.
  • Equivalence Point
    The stage in titration where the amount of acid equals the amount of base.
  • pKa
    The pH value at which an acid-base indicator changes color, ideally close to the equivalence point.
  • Conjugate Form
    The form of an indicator after it has gained or lost a proton, resulting in a color change.
  • Titration Curve
    A graph showing the pH change of a solution as a titrant is added, used to identify the endpoint.
  • Methyl Orange
    An indicator that transitions from red to yellow over a pH range of 3.3 to 4.5.
  • Thymol Blue
    An indicator with two pH transition ranges: 1.2-2.8 (red to yellow) and 8-9.2 (yellow to blue).
  • Weak Acid
    An acid that partially dissociates in solution, often used as an indicator in titrations.
  • Weak Base
    A base that partially dissociates in solution, often used as an indicator in titrations.
  • Color Transition
    The change in color of an indicator as it shifts from its weak form to its conjugate form.
  • pH Range
    The span of pH values over which an indicator changes color, typically within one unit of its pKa.
  • Buffer Solution
    A solution that resists pH change, related to the pH range of an indicator.