Definition

Noun: 1. A type of synthetic yellow dye: Alizarin yellow refers to any of several yellow synthetic dyes used as acid-base indicators in chemistry. Despite the name, these dyes are not chemically related to alizarin (a red dye) but are applied in similar ways, typically for staining or as pH indicators.

Usage Examples

• The laboratory used alizarin yellow as a pH indicator to test the acidity of the solution.
• Under the microscope, the tissue sample was stained with alizarin yellow for better contrast.
• A drop of alizarin yellow changed color, indicating the endpoint of the titration.

Advanced Usage

• As a pH indicator: Alizarin yellow dyes are commonly used to determine the pH range of a solution, with color changes occurring at specific acidity or alkalinity levels.
  • Alizarin yellow R changes from yellow to red in the pH range of 10.1 to 12.0.

Variants and Related Words

• Alizarin yellow R: A specific, commonly used variant of this dye class.
• pH indicator: The general functional category to which alizarin yellow belongs.
• Acid-base indicator: A synonym for pH indicator.

Synonyms

• Yellow dye
• Acid-base indicator (in the context of its function)
• pH indicator (in the context of its function)

Notes on Meaning

• The key distinction in the definition is that alizarin yellow is named for its application method, not its chemical structure. It is crucial to understand it is not a yellow form of alizarin but a separate class of compounds used similarly.

Noun

1. any of various yellow dyes; not related chemically to alizarin but applied in the same manner