Iodine indicates the presence of starch in a solution by altering the energy level spacing in the amylose component of starch, creating an intense blue color. This energy change allows amylose to absorb visible light.
When iodine and starch interact, iodine molecules become arranged within the starch molecules in a linear fashion. The visible end result of this arrangement is the appearance of a blue-black coloration.
Iodine reacts with starch in water to produce an intensely blue color. Beta amylose, which is a form of soluble starch, traps iodine ions within its highly coiled structure to achieve this effect.
Iodine stains starch because of the chemical reaction between it and the polysaccharides in starch molecules. This reaction turns the starch a deep blue hue. This phenomenon is called Lugol's reaction for starch. Iodine is useful in laboratories and medical offices beca...
Starch when mixed with Iodine turns a deep shade of blue because starch contains amylose. Amylose is a soluble component of starch as well as other carbohydrates.
Starch has the largest molecule out of all of starch, iodine and water. This is because it is composed of numerous units of glucose, so it's technically a polymer.
According to WebMD, iodine is commonly used to prevent iodine deficiency and disinfect wounds. It can also be used to protect against radiation, treat ulcers and purify water.