Chlorophenol red

Chlorophenol red
Skeletal formula of chlorophenol red in cyclic form
Ball-and-stick model of the chlorophenol red molecule in cyclic form
Names
Preferred IUPAC name
3,3-Bis(3-chloro-4-hydroxyphenyl)-2,1λ6-benzoxathiole-1,1(3H)-dione
Other names
3′,3′-Dichlorophenolsulfonaphthalein
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.022.382 Edit this at Wikidata
EC Number
  • 224-619-2
UNII
  • InChI=1S/C19H12Cl2O5S/c20-14-9-11(5-7-16(14)22)19(12-6-8-17(23)15(21)10-12)13-3-1-2-4-18(13)27(24,25)26-19/h1-10,22-23H ☒N
    Key: WWAABJGNHFGXSJ-UHFFFAOYSA-N ☒N
  • InChI=1/C19H12Cl2O5S/c20-14-9-11(5-7-16(14)22)19(12-6-8-17(23)15(21)10-12)13-3-1-2-4-18(13)27(24,25)26-19/h1-10,22-23H
    Key: WWAABJGNHFGXSJ-UHFFFAOYAK
  • C1=CC=C2C(=C1)C(OS2(=O)=O)(C3=CC(=C(C=C3)O)Cl)C4=CC(=C(C=C4)O)Cl
Properties
C19H12Cl2O5S
Molar mass 423.26 g·mol−1
Melting point 261 °C (502 °F; 534 K)[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Chlorophenol red (pH indicator)
below pH 5.4 above pH 6.8
5.4 ⇌ 6.8

Chlorophenol red is an indicator dye that changes color from yellow to violet in the pH range 5.4 to 6.8.[2] The pH of a substance is determined by taking the negative logarithm of the Hydronium ion concentration and the indictor changes color due to the dissociation of H+ ions.[3] The lambda max is at 572 nm.[4]

  1. ^ Haynes, p. 3.116
  2. ^ Haynes, p. 8.88
  3. ^ "pH Indicators". Chemistry LibreTexts. 2013-10-02. Retrieved 2021-03-14.
  4. ^ "Chlorophenol Red".