Starch indicator is widely used in analytical chemistry, particularly in iodometric titrations, to detect the presence of iodine. When iodine is added to a solution containing starch, it forms a deep blue or blue-black complex, making it easier to visually identify the endpoint of the titration. This application is especially useful in determining the concentration of oxidizing or reducing agents in a sample. For example, it is commonly employed in the titration of vitamin C (ascorbic acid) or in water quality testing to measure chlorine levels. The starch indicator provides a clear and precise color change, ensuring accurate and reliable results in quantitative analysis.