Chlorophenol red

Chlorophenol red
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
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)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references
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. 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. The lambda max is at 572 nm.