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ERIC Number: EJ913047
Record Type: Journal
Publication Date: 2010-Jan
Pages: 4
Abstractor: As Provided
Reference Count: 15
ISSN: ISSN-0021-9584
Developing an Invisible Message about Relative Acidities of Alcohols in the Natural Products Henna, Turmeric, Rose Petals, and Vitamin A
Dewprashad, Brahmadeo; Hadir, Latifa
Journal of Chemical Education, v87 n1 p36-39 Jan 2010
An engaging and colorful demonstration was developed that illustrates the utility of resonance theory in predicting the relative acidities of alcohols. The demonstration can be used as an introduction to exercises that provide students with practice in writing resonance structures and in predicting relative acidities. The demonstration exploits the pH-dependent structural and color changes that result in three naturally occurring dyes. Dilute basic solutions are used to write invisible messages and ethanolic extracts from henna, turmeric, and roses are used as developing solutions. The demonstration can be quickly, easily, and safely prepared for use and was found to be effective in attracting students' attention and leading to lively discussions of resonance stabilization, keto-enol tautomerization, and relative acidities. (Contains 2 figures.)
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A