Dimethyl yellow pH indicator
Description
Dimethyl yellow is a synthetic azo dye used as a pH indicator in analytical chemistry, changing color from red below pH 2.9 to yellow above pH 4.0. It appears as a yellow-orange to orange-brown powder and is suitable for titrations involving weak bases with strong acids.
Chemical Properties
Chemical name: Dimethyl yellow (also Methyl Yellow or 4-(Dimethylamino)azobenzene)
Synonyms: Solvent Yellow 2, C.I. 11020.
CAS number: 60-11-7.
Molecular formula: C₁₄H₁₅N₃ or C₆H₅N=NC₆H₄N(CH₃)₂.
Molecular weight: 225.29–225.30 g/mol.
Melting point: 110–116 °C.
Appearance: Yellow powder or orange to brown crystalline powder.
Density: ~1.14 g/cm³.
λ max: 403–407 nm in ethanol; 505–515 nm at pH 2.4.
Applications
Primarily used as an acid-base indicator in pH titrations, especially for weak base-strong acid endpoints.
Employed in analytical procedures requiring sharp color change in acidic range; typically prepared as 0.1% solution in ethanol.
Storage and Handling
Store in a cool, dry place in tightly closed containers, protected from light and moisture.
Toxic if swallowed with potential carcinogenic effects; handle with gloves, avoid inhalation and skin contact, and prevent environmental release.
For laboratory research use only; not for food, drug or cosmetic applications.
Specifications
| Model No. | N-CH1720 |
|---|
