Author(s):

Shubhangi Kshirsagar, Ujwala Dube, Suchita Gokhale, Nilofar Abid Khan, Gayatri G Varma and Pranali Sonawane

Abstract: Indicator is a chemical agent which is used to recognize the attainment of end point in titration. After the reaction between the chemical and the standard solution is complete, the indicator should give a color change. A pH indicator is a chemical which changes the color of solution with change in pH in response to a chemical change. An acid-base indicator changes its color depending on pH change. Redox indicators are also commonly used (eg. - methylene blue). Synthetic indicators are frequently used in acid-base titrations. As synthetic indicators have certain drawback like unavailability, expensive. An experiment has been made to recognize the indicator property of various natural pigments. The main goal of this attempt is to replace the synthetic indicators. Natural indicators are inexpensive as compare to synthetic indicators. Ethanolic extract of Withania somnifera (Ashwagandha) and Curcuma longa (Turmeric) were evaluated and sample extract gives sharp and intense color change. Phenolphthalein was used as a standard indicator to compare the color change of sample extract. Result proved sample extracts to be acceptable as substitute of synthetic indicators in acid-base titrations.

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