The use of different plant pigments from flowers and fruits as acid-base titration indicators
No Thumbnail Available
Date
2024
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Busitema University
Abstract
This study aimed to determine the pKa values of plant pigments extracted from selected fruits and flowers and evaluate their suitability as natural pH indicators in various acid-base titrations. The research involved extracting pigments from species such as Peacock flower, Mexican Sunflower, Cascabela, Spectabilis, Eggplant, Apple, Tomato, and Lantana, followed by their application in titrations involving NaOH vs. HCl, NaOH vs. CH₃COOH, NH4OH vs. HCl, and NH4OH vs. CH₃COOH. The pH of neutralization was determined for each titration, and the corresponding pKa values were calculated. The effectiveness of each pigment as an indicator was assessed based on the alignment of the pKa values with the pH at the point of neutralization and the clarity of the observed color changes. The results revealed that pigments from the Mexican Sunflower, Cascabela, and Apple were particularly effective as natural indicators, exhibiting clear color transitions such as brown to colorless and yellow to colorless, with pKa values closely matching the titration endpoints. In contrast, Lantana pigments were found unsuitable for all titrations due to significant discrepancies between their pKa values and the neutralization points, resulting in unclear color changes. The study highlights the potential of these natural pigments as eco-friendly alternatives to synthetic indicators, especially in educational and environmentally conscious applications. Based on these findings, the study recommends further research into additional plant species to expand the pool of effective natural indicators and refine extraction methods to optimize yield and purity. The potential for wider application of these pigments in areas such as pH sensitive packaging, food, and cosmetics is also suggested. This research underscores the viability of using natural substances in chemical processes, contributing to more sustainable laboratory practices and offering valuable teaching tools in educational settings
Description
Keywords
Citation
Opolot, H. J. (2024). The use of different plant pigments from flowers and fruits as acid-base titration indicators [Undergraduate, Research Report]. Busitema University.