Roselle calyx (Zoborodo) as a substitute to organic indicator (methyl orange)

Abstract

Roselle calyx samples were dried, pulverized into powder and extracted with distilled water for 24 hours by maceration method. The acidity and alkalinity indicator properties of the extracts were tested with prepared acid and base solutions. The results showed colour change with all the samples. But titration using the samples as indicator shows that only the end points of the purple sample matched well with that obtained using conventional (methyl orange) indicator. The study recommends the use of the purple variety as substitute to standard indicator in volumetric analysis.

Keywords: Roselle Calyx, Indicator, Volumetric, Gravimetric