When specimen X is mixed with few drops of iodine solution, the appearance of a blue-black colour confirms that X is

When specimen X is mixed with a few drops of iodine solution and a blue-black color appears, it confirms that X is starch. Iodine solution is commonly used to test for the presence of starch in a sample. Iodine reacts with the starch molecule to form a dark blue or black color, indicating the presence of starch. Starch is a complex carbohydrate that is found in many plant-based foods, such as potatoes, rice, and wheat. It is made up of many glucose molecules linked together in a chain-like structure. When iodine solution is added to a sample that contains starch, the iodine molecules are able to fit in between the glucose molecules in the starch chain, forming a complex that reflects light differently and giving the blue-black color. In summary, the appearance of a blue-black color when specimen X is mixed with iodine solution confirms that X is starch.