Résumé
Indicators are used to determine the equivalence point in acid � base titrations (neutralization titrations). They exhibit sharp color change with respect to change in pH. Popularly used indicators for neutralization titrations are synthetic chemicals. They are found to have hazardous effects in human body. The highly colored pigments obtained from plants are found to exhibit color changes with variation in pH. A study was done to check the indicator action of aqueous extract of flower pigments and compared with that of already existing synthetic indicators. Extraction was done using hot water and a definite volume of extract was added which gave accurate and reliable results for different types of neutralization titrations - strong base against strong acid, strong acid against a weak base, weak base against strong acid and weak acid against weak base. The work proved to be acceptable in introducing flower pigments as a suitable substitute to the synthetic indicators.
Résumé
Indicators help to determine the equivalence point in acid – base titrations (neutralization titrations). They show sharp color change with respect to change in pH. Commonly used indicators for neutralization titrations are synthetic in nature. They are found to posses hazardous effects in human body. The highly colored pigments obtained from plants are found to exhibit color changes with variation of pH. A study has been done to investigate the indicator activity of aqueous extract of flower pigments and compared with that of already existing synthetic indicators. Pigments were extracted using hot water and a definite volume was added which gave accurate and reliable results for all the four different types of neutralization titrations - strong acid against strong base, strong acid against a weak base, weak acid against strong base and weak acid against weak base. The work proved to be acceptable in introduc-ing flower pigments as a substitute to the synthetic acid-base indicators.
Résumé
Indicators help to determine the equivalence point in acid – base titrations (neutralization titrations). They show sharp color change with respect to change in pH. Commonly used indicators for neutralization titrations are synthetic in nature. They are found to posses hazardous effects in human body. The highly colored pigments obtained from plants are found to exhibit color changes with variation of pH. A study has been done to investigate the indicator activity of aqueous extract of flower pigments and compared with that of already existing synthetic indicators. Pigments were extracted using hot water and a definite volume was added which gave accurate and reliable results for all the four different types of neutralization titrations - strong acid against strong base, strong acid against a weak base, weak acid against strong base and weak acid against weak base. The work proved to be acceptable in introduc-ing flower pigments as a substitute to the synthetic acid-base indicators.