Original Articles
James G Mayeka and Faith P Mab
Abstract
Currently, the conduction of acid-base chemical reactions involves the use of industrial made indictors which are associated with environment pollutions. This situation necessitates the search for more acid-base indicators from the natural sources. The aim of this work was to study the acid-base indicating capacity of the extracts from Synadenium glaucescens. To study the indicating capacity from S. glaucescens, the extracts from leaves, stem and root barks were studied for their colour change, reversibility, pH range and effectiveness during titration by titration using strong and weak acids and bases. The results indicated that, only the indicators from stem and root barks extracts had indicating capacity as they were capable to change colour due to pH change. The pH range of the two indicators was from 2.9 to 12.7 which make them to be better universal indicators. Both indicators could be reversed clearly while in acidity and alkalinity conditions. Titration showed sharp colour change at the end points. The mean titre of the two indicators were ranging from 24.3 ± 0.31 to 25.4 ± 0.75 and 18.9 ± 0.17 to 24.1 ± 0.05, respectively with their colour change from brick red to colourless and orange to colourless, respectively. The end points obtained by stem and root barks indicators correspond to the end points obtained by standard indicators, phenolphthalein and methyl orange. Thus, the stem and root barks extracts are suitable to serve as acid-base indicator. Further studies could be done aiming to develop paper indicators and isolate pure compound which is responsible for indicating capacity of S. glaucescens.