Question

Conduct an activity to show that saliva acts on starch
and convert it into sugar using iodine

Answer 1

Answer:

Here

Explanation:

Experiment to show the effect of saliva on starch

Two test tubes were taken and were labeled A and B.

In test tube A one teaspoon full of boiled rice was kept.

In test tube B one teaspoon full of boiled rice which were chewed for 3-5 minutes were kept.

3-4 ml of water was added to both the tubes.

Then 2-3 drops of iodine solution was added to both test tubes A and B.

Observation:

The test tube A shows blue – black colour whereas test tube B does not show this colour.

Conclusion:

Since test tube B has boiled rice which were chewed for 3-5 minutes, the saliva present in mouth has acted upon starch to break down into sugars. So it does not show any colour in presence of iodine solution.

Boiled rice in test tube A has not been exposed to saliva, so starch is present which is indicated by blue-black colour on addition of iodine solution.