Full Length Research Paper

Comparism of Cola acuminata (Kola nut) fruit extract as natural indicator with standard indicators: Improvisation imperative in Nigeria school chemistry

Sofeme R.J.1 and Andy, N.M.2

Abstract

Chemistry education takes a center position in science and technology. Acid-base titration is an important aspect of practical that requires chemicals and compulsory for senior secondary certificate examinations in Nigeria. In acid base titrations, indicators are employed to show a sharp color change at interval of pH. Natural pigments in plants known as anthocyanins are highly colored substances and may show color changes with variation of pH. An attempt has been made to compare the indicator activity of ethanolic fruit extract of Cola acuminata with methyl orange and phenolphthalein indicators in strong acid strong base titrations at 0.1M and 0.5M concentrations respectively. The research is to see if ethanolic fruit extract of C. acuminata can replace the synthetic indicators as they contain certain disadvantages like chemical pollution, availability problem and high cost. Ethanolic fruit extract of cola acuminate gives sharp and intense color changes as compared to phenolphthalein and methyl orange at different concentrations. The equivalent points obtained by the C. acuminata fruit extract coincided with that of methyl orange. Ethanolic fruit extract of C. acuminata was found to be very useful, economical, simple, inert and accurate for acid base titrations.

Key words: Cola acuminata, standard acid base indicator; natural indicator, ethanolic extract.

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