AP BIOLOGY

Detailed explanation-1: -In the presence of starch, iodine changes its color from brown to blue-black or purple. So, iodine can be used to test the presence of starch.

Detailed explanation-2: -Starch Test: Add Iodine-KI reagent to a solution or directly on a potato or other materials such as bread, crackers, or flour. A blue-black color results if starch is present. If starch amylose is not present, then the color will stay orange or yellow.

Detailed explanation-3: -The iodine test is used to check the availability of starch like carbohydrates in a sample. Starch changes to a deep “blue-black” colour upon addition of aqueous solutions of the triiodide anion, because of the production of an intermolecular charge transfer component (complex).

Detailed explanation-4: -Explanation: The presence of starch in leaves can be tested by the Iodine test. When we remove chlorophyll from the leaf by boiling it in alcohol and then putting two drops of iodine solution, it is a colour change to blue indicates the presence of starch.

Detailed explanation-5: -Final answer: The presence of starch can be tested by using iodine.