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Usefulness of Some Plant Flowers as Natural Acid‐Base Indicators
Author(s) -
Soltan M. E.,
Sirry S. M.
Publication year - 2002
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200200011
Subject(s) - chemistry , hibiscus , base (topology) , potentiometric titration , acid–base titration , ceiba , titration , environmental chemistry , botany , organic chemistry , ecology , ion , mathematical analysis , mathematics , biology
Environmental protection must require the use of natural products instead of chemicals to minimize pollution. Thus, this investigation studies the use of some plant flowers as naturally occurring acid‐base indicators. We utilized plant flowers of Celosiacristate Linn, Bombax ceiba L., Poincianaregia and Hibiscus subdariffa . These flowers contain anthocyanine pigments whose colour depends on pH; there fore they are used as pH indicators. The acid‐base equilibria of these pigments were investigated using spectro photometric and potentiometric methods. The pk values are 9.6 for Celosiacristate Linn, 5.7 for Bombax ceiba L., 8.6 for Poincianaregia and 2.8 & 7.3 for Hibiscus subdariffa . Experimentation of these indicators on different concentrations of acid‐base titrations in the presence of variable concentrations exhibited similar results as for synthetic indicators.