What happen when you mix biscuit and iodine?

When you mix biscuit and iodine, the iodine can interact with the starches present in the biscuit. If the biscuit contains starch, the iodine will turn a blue-black color, indicating the presence of starch. This reaction occurs because iodine molecules fit inside the helical structure of starch, forming a complex. If the biscuit does not contain starch, there will be no significant color change.