Acid-base indicator

{
  "id": "MLC-T-CHM-000138",
  "term": "Acid-base indicator",
  "field": "Chemistry",
  "definition": "A weak organic acid or base that changes color over a specific pH range, used to visually signal the equivalence point in an acid-base titration. The color change occurs when the indicator undergoes a structural rearrangement due to protonation or deprotonation. Phenolphthalein and methyl orange are common examples.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "titrant",
    "titration"
  ],
  "references": [
    "Orange Book, 2nd ed., p. 48 (https://media.iupac.org/publications/analytical_compendium/)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/acid-base-indicator/"
}