Methyl orange

• CAT Number: R071069
• CAS Number: 547-58-0
• Molecular Formula: C14H14N3NaO3S
• Molecular Weight: 327.33
• Purity: ≥95%
• Synonyms: SODIUM 4-(4-DIMETHYLAMINOPHENYLAZO)BENZENESULFONAT
• Storage: RT
• IUPAC Name: sodium;4-[[4-(dimethylamino)phenyl]diazenyl]benzenesulfonate
• InChI: InChI=1S/C14H15N3O3S.Na/c1-17(2)13-7-3-11(4-8-13)15-16-12-5-9-14(10-6-12)21(18,19)20;/h3-10H,1-2H3,(H,18,19,20);/q;+1/p-1
• InChIKey: STZCRXQWRGQSJD-UHFFFAOYSA-M
• SMILES: CN(C)C1=CC=C(C=C1)N=NC2=CC=C(C=C2)S(=O)(=O)[O-].[Na+]

Methyl orange（Cat No.:R071069）is a pH-sensitive azo dye indicator with the molecular formula C14H14N3NaO3S. It appears orange in neutral solutions and changes to red under acidic conditions, with a transition range between pH 3.1 and 4.4. Commonly used in titrations involving strong acids and weak bases, methyl orange provides a clear and sharp endpoint due to its distinct color shift. It is also employed in educational demonstrations and analytical chemistry. As an azo compound, it contains a –N=N– linkage, and its vivid color and solubility in water make it a reliable laboratory reagent.