ABSTRACT:
The substance which causes change in colour with respect to change in pH of solution is termed as acid-base indicator. At different pH range every indicator shows different range of colors. There are numbers of chemical or synthetic indicators which are used in acid-base titration but these are slight costlier and not available easily every time hence natural indicator i.e. obtained from plant source are come forth, because plants easily available everywhere extraction process is less expensive. We use Passionflower and phenolphthalein as indicators in titration s of strong acid-strong base (HCl and NaOH), strong acid–weak base (HCl and NH3), and weak acid-strong base (CH3COOH and NaOH) and weak acid-weak base (CH3COOH and NH3). The result obtained from titration of natural indicator ( i.e. passionflower extract ) are near to the result obtained from titration of standard indicator(i.e. phenolphthalein).in this research work we successfully prove that natural indicator can also used in titration.