Title: precipitation indicator
Long Title: IUPAC Gold Book - precipitation indicator
DOI: 10.1351/goldbook.09048
Status: current

Definition
Visual indicator precipitated, with concomitant color change, by reaction with excess titrant at the end-point of a titration.

Example
Mohr method for chloride analysis by titration with silver nitrate using chromate (\(\ce{CrO4^{2−}}\)) as indicator. The end-point of the titration occurs when all the chloride ions are precipitated. Then additional silver ions react with the chromate ions of the indicator to form a red-brown precipitate of silver chromate.

Source
- PAC, 2025, 97, 137. 'Glossary of terms for mass and volume in analytical chemistry (IUPAC Recommendations 2024)' on page 5 (https://doi.org/10.1515/pac-2023-0903)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/09048/html
- json: https://goldbook.iupac.org/terms/view/09048/json
- xml: https://goldbook.iupac.org/terms/view/09048/xml

Citation: Citation: 'precipitation indicator' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09048
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Accessed: 2026-04-18T14:45:49+00:00