P

Phenolphthalein

IUPAC: 3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one

C20H14O4 Indicators CAS 77-09-8
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Quick Reference
Formula / NotationC20H14O4
CAS Number77-09-8
Molecular Weight318.3
Melting Point496 to 504 °F (NTP, 1992)
Density1.299 at 77 °F (NTP, 1992) - Denser than water; will sink
Solubilityless than 1 mg/mL at 66 °F (NTP, 1992)
AppearancePhenolphthalein appears as white or yellowish-white to pale orange fine crystalline powder. Odorless. Aqueous solution is acidic. Colorless to pH 8.5; pink to deep-red above pH 9. Colorless in pres...
Also Known As3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one; 77-09-8; Phthalimetten; Euchessina; Phenolax; Phthalin; Espotabs; Purgophen; Koprol; Laxogen
CategoryIndicators

What is Phenolphthalein?

Phenolphthalein can cause cancer according to The Food and Drug Administration (FDA) and The National Toxicology Program.

Formula & Notation

C20H14O4

IUPAC Name: 3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one

Other Names / Synonyms: 3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one; 77-09-8; Phthalimetten; Euchessina; Phenolax; Phthalin; Espotabs; Purgophen; Koprol; Laxogen

Properties & Characteristics

Appearance: Phenolphthalein appears as white or yellowish-white to pale orange fine crystalline powder. Odorless. Aqueous solution is acidic. Colorless to pH 8.5; pink to deep-red above pH 9. Colorless in pres.... Molecular formula: C20H14O4. Molecular weight: 318.3 g/mol. Melting point: 496 to 504 °F (NTP, 1992). Density: 1.299 at 77 °F (NTP, 1992) - Denser than water; will sink. Solubility: less than 1 mg/mL at 66 °F (NTP, 1992). Vapor pressure: 6.7X10-13 mm Hg @ 25 °C /Estimated/. LogP: 3.6.

Physical Data

PropertyValue
Melting Point496 to 504 °F (NTP, 1992)
Density1.299 at 77 °F (NTP, 1992) - Denser than water; will sink
Molecular Weight318.3
Solubilityless than 1 mg/mL at 66 °F (NTP, 1992)
AppearancePhenolphthalein appears as white or yellowish-white to pale orange fine crystalline powder. Odorless. Aqueous solution is acidic. Colorless to pH 8.5; pink to deep-red above pH 9. Colorless in pres...

Uses & Applications

Used as a pH indicator in acid-base titrations, analytical chemistry, and chemical education demonstrations.

Safety Information

May be irritant or toxic in concentrated form. Handle with care. Consult SDS before use.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Phenolphthalein
Formula C20H14O4
CAS Number 77-09-8
Molecular Weight 318.3
Category Indicators
Synonyms 3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one; 77-09-8; Phthalimetten; Euchessina; Phenolax; Phthalin; Espotabs; Purgophen; Koprol; Laxogen

Frequently Asked Questions

Phenolphthalein can cause cancer according to The Food and Drug Administration (FDA) and The National Toxicology Program.

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.