The equilibrium constant for bromothymol blue: A general chemistry laboratory experiment using spectroscopy

Elsbeth Klotz, Robert Doyle, Erin Gross, Bruce Mattson

Research output: Contribution to journalArticle

19 Scopus citations


A simple, inexpensive, and environmentally friendly undergraduate laboratory experiment is described in which students use visible spectroscopy to determine a numerical value for an equilibrium constant, Kc. The experiment correlates well with the lecture topic of equilibrium even though the subject of the study is an acid-base indicator, bromothymol blue. The experiment gives excellent results and offers an inexpensive, zero-waste alternative to traditional equilibrium experiments, such as the Fe(SCN) 2+ equilibrium.

Original languageEnglish (US)
Pages (from-to)637-639
Number of pages3
JournalJournal of chemical education
Issue number5
StatePublished - May 1 2011


All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Education

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