An iodine solution is placed on the cut side of a potato. With in seconds, a blue-black color appears thus showing "positive test for starches".
Option: B
Explanation:
Amylose in starch is accountable in the existence of iodine for production of a deep blue shade. Within the amylose coil the iodine molecule slips. Attach a solution or directly to a potato or other products such as pasta, crackers, or flour with Iodine-KI reagent. If starch is available a blue-black color results.
If starch amylose is not available then orange or yellow will remain the color. Variations in some inorganic reactions to the reduction of oxidation, iodine may be used as an indicator for following changes in iodide ion and iodine product. Soluble solvent is applied to the starch.
