TITLE:
Comparative Study on the Acid-Base Indicator Properties of Natural Dye, Turmeric Rhizome (Curcuma longa) and Synthetic Dyes
AUTHORS:
Genevive Chinyere Onuegbu, Onyekachi Onyinyechi Nnorom, Gerald Okwuchi Onyedika
KEYWORDS:
Turmeric Rhizome, Extraction, Acid-Base Indicator, Methyl Orange, Phenolphthalein
JOURNAL NAME:
Journal of Textile Science and Technology,
Vol.9 No.1,
February
15,
2023
ABSTRACT: Acid-Base Indicator, Turmeric Rhizome (Curcuma longa) was extracted from the root of a turmeric plant. The
turmeric was peeled, washed and dried in an oven at 60°C. It was ground into powder and soaked in hot
and cold ethanol for the extraction. The extract was filtered and part of it
was concentrated to yield a reasonable quantity of turmeric indicator. On
standardization of acid with a base, 0.05 M base
respectively of Sodium hydroxide (NaOH), sodium carbonate (Na2CO3)
and Disodium borate (B4Na2O7) were used. Hot
and cold extracts of turmeric were used as indicators and were compared with
methyl orange and phenolphthalein. On the preliminary test carried out, hot and
cold turmeric indicator showed yellow colour in acid medium and orange colour
in the base. Methyl orange showed red colour in acid but yellow in the base, phenolphthalein
was colourless in acid but pink in the base. During titration there were colour
changes at the end points in the entire test carried out. The average volumes
at ends points were calculated, the molar concentrations and mass
concentrations of the acids used were also determined. The results showed that
there was no difference between the natural indicators used and the existing
synthetic indicators which are toxic to our environment.