An Overview of the Use of Natural Indicators in Acid-Base Titrations

Abstract

While titrimetric and gravimetric analysis were the most concerning analytical techniques, they are now the most commonly used techniques for identifying chemicals. The endpoint in the titrimetric analysis method is identified by colour changes from one medium to another caused by the addition of chemicals referred to as indicators. There are a lot of synthetic indicators on the market these days, which are expensive and pollute the environment. Human toxicity is produced by a number of synthetic markers. As demonstrated by their use in acid-base titrimetric analysis, floral extracts have a very promising analytical potential. Seven plant extracts were found to function well in strong acid-strong base titrations: violet cabbage, beetroot, red hibiscus flower (shoe flower), turmeric powder, red rose flower, henna leaves, and pink Mirabilis Jalapa flower (4 o'clock flower). For the violet cabbage, there was a noticeable and distinct colour shift from pale pink to violet; for the beetroot, it was dark brown to red; and for the red hibiscus flower extract, it was pale yellow to pink.