Question

Refer the given experiment. What can you conclude from it?

• A. Boiled rice does not contain starch.
• B. Saliva reacts with iodine solution and alters its property.
• C. Saliva converts starch to sugars, which do not give blue-black colour with iodine.
• D. All of the above.

Answer 1

Answer: (C)

Saliva converts starch to sugars, which do not give blue-black colour with iodine.

The process of digestion begins in the mouth. Saliva secreted by the salivary glands can convert starch into sugars. When some boiled rice is taken in a test tube and a few drops of iodine solution are poured into it, we see violet colour. But when we add some boiled rice with saliva it will not give violet colour because saliva contains amylase which converts the starch into the simple sugar. Thus, on the addition of iodine solution, it does not give violet but reddish-brown colour.