Abstract:

The present study was designed to evaluate the juice extracted from flower petals (bracts) of climbing woody vine Bougainvillea glabra Choisy (Nyctaginaceae) as a titration indicator. A comparative study of Bougainvillea juice, a natural indicator, with synthetic indicator viz. phenolphthalein, methyl orange and neutral red-methylene blue were carried out to evaluate the accuracy of Bougainvillea juice as an acid-base indicator. The results indicated that juice obtained from flowers of Bougainvillea glabra can be used as acid base indicator in titration of strong acid with strong base because similar results were obtained by phenolphthalein and the rationale behind using Bougainvillea juice in preference to phenolphthalein is its easy availability, inertness, ease of preparation and cost-effectiveness and also the indicator papers prepared using Bougainvillea juice can be used to differentiate solutions in pH range of 7–10 because it showed different colors at each pH from 7–10.