Used to detect the presence of starch in various samples. When added to a substance containing starch, the solution turns deep blue or black due to the formation of a starch-iodine complex. Commonly applied in laboratory testing, food analysis, and educational experiments to demonstrate carbohydrate identification. Also utilized in water treatment testing to check for organic contamination and in pharmaceutical formulations for quality control. Its simplicity and visible color change make it a reliable indicator in both field and laboratory settings.