Abstract

PALACIO, Soraya Moreno; OLGUIN, Conceição de Fátima Alves  and  DA CUNHA, Márcia Borin. Determination of acids and bases by extracts of flowers. Educ. quím [online]. 2012, vol.23, n.1, pp.41-44. ISSN 0187-893X.

The teaching of chemistry, through experimental classes, with easily obtained materials, has been an alternative to stimulate teachers and students the learning of concepts, often abstract and difficult to understand. We present a proposal for experimental work to determine the acid or basic character of a solution, using an extract of flowers of Hibiscus rosa-sinensis and Catharanthus roseus. Both plants are from China but actually easily founded in our gardens. The color of the flowers varies from white to red and can be used as an acid-base indicator due to some changes in the structure of the anthocyanin.

Keywords : flowers; acid-base; indicators; experimental work.