Author(s): Vinayak S Marulkar, Shrikant S Kavitake, Suresh G Killedar,Dipak P Mali
Synthetic indicators have been tried as indicators in acid-base titrations but due to environmental pollution, availability and cost, natural compounds are best alternate. Natural pigments in plants are highly colored substances and may show sharp color changes with variation in pH .An attempt has been made to extract natural indicator by maceration from stem bark of Boerhavia erecta Linn. The equivalence points obtained by the BEI strong acid-strong base, strong acid-weak base, weak acid-strong base and weak acid weak base titrations were coincident with the equivalence points obtained by synthetic indicators. Thus natural indicator was found to be eco-friendly, economical, simple and accurate for all acid-base titrations. Phytochemical analysis and spectral studies confirmed presence of anthocyanins and flavonoids in BEI responsible for accurate and sharp colour change at equivalence point. The present study reports the use of this natural indicator in different acid base titrations.