Resorcinolphthalein (Noun)
Meaning
A yellow dye that is visible even when highly diluted; used as an absorption indicator when silver nitrate solution is added to sodium chloride in order to precipitate silver chloride (turns pink when no chloride ions are left in solution and negative fluorescein ions are then absorbed).
Classification
Nouns denoting substances.
Examples
- The chemical indicator resorcinolphthalein is used to detect the presence of chloride ions in a solution.
- In the lab, resorcinolphthalein was added to the sodium chloride solution to indicate when all the chloride ions had been precipitated.
- When the silver nitrate solution was added to the mixture containing resorcinolphthalein, the color changed from yellow to pink as the chloride ions were depleted.
- The student added a few drops of resorcinolphthalein to the solution and observed the color change as the silver chloride precipitated.
- The yellow color of the resorcinolphthalein indicator remained until the chloride ions were completely consumed, at which point it turned pink.