File:Phenolphthalein.svg · Wikimedia Commons · See Wikimedia Commons
phenolphthaleina
Sign in to saveAlso known as Alpha-di(p-hydroxyphenyl)phthalide, 3,3-Bis(p-hydroxyphenyl)phthalide, 3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone, 3,3-Bis(4-hydroxyphenyl)phthalide, 3,3-Bis(4-hydroxyphenyl)-2-benzofuran-1(3H)-one, Dihydroxyphthalophenone, Ex-Lax, Prulet
Phenolphthalein ( ) is a chemical compound with the formula C20H14O4 and is often written as "HIn", "HPh", "phph" or simply "Ph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions. It belongs to the class of dyes known as phthalein dyes.
Phenolphthalein is a chemical compound that changes color depending on whether a solution is acidic or basic—turning colorless in acids and pink in bases. It's commonly used in chemistry labs to help determine when a chemical reaction reaches the right balance during acid-base testing.
AI-generated from the Wikipedia summary — may contain errors.
Chemical data
- Formula
- C20H14O4
- Molecular weight
- 318.3 g/mol
- IUPAC name
- 3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one
- SMILES
- C1=CC=C2C(=C1)C(=O)OC2(C3=CC=C(C=C3)O)C4=CC=C(C=C4)O
- InChIKey
- KJFMBFZCATUALV-UHFFFAOYSA-N
- XLogP
- 3.6
- Polar surface area
- 66.8 Ų
- H-bond donors
- 2
- H-bond acceptors
- 4
- Formal charge
- 0
via PubChem
~8 min read
Encyclopedic overview
11 sectionsContents
- Uses
- pH indicator
- Carbonation of concrete
- Education
- Entertainment
- Detection of blood
- Laxative
- Synthesis
- See also
- References
- External links
Phenolphthalein ( ) is a chemical compound with the formula C20H14O4 and is often written as "HIn", "HPh", "phph" or simply "Ph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions. It belongs to the class of dyes known as phthalein dyes.
Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols in experiments. It is a weak acid, which can lose H+ ions in solution. The nonionized phenolphthalein molecule is colorless and the double deprotonated phenolphthalein ion is fuchsia. Further addition of hydroxide in higher pH occurs slowly and leads to a colorless form, since the conjugated system is broken. Phenolphthalein in concentrated sulfuric acid is orange-red due to protonation and creation of a stabilised trityl cation.
Excerpted from Wikipedia’s “phenolphthaleina” article, available under the CC BY-SA 4.0 licence.