Boiled rice chewed inside our mouth for few minutes ,is taken
out in a dish and iodine is added to it.What will we observe and
why?
Answers
- The boiled rice which was not chewed will turn blue black when we put iodine solution.... Saliva will break down the starch into sugar when iodine solution is mixed. and does not turn blue black in colour when drops of iodine solution is mixed with chewed boiled.
When boiled rice chewed inside our mouth is taken out and iodine is added to it, we observe that the rice does not turn into black blue colour as oppossed to boiled rice which is not chewed.
Explanation:
To understand the given situation, let us do an experiment with boiled rice that is chewed and with one that is not chewed. This experiment will show us the effect of saliva on starch (i.e. Boiled rice).
EXPERIMENT:
1) Let us take two test tubes and label them as A and B.
2) Test tube A contains one teaspoon full of boiled rice.
3) Test tube B contains one teaspoon full of chewed boiled rice.
4) Around 3-4 ml of water is added to both the test tubes.
5)Then the most crucial step is to add 2-3 drops of iodine solution to both test tubes A and B.
Observation:
The test tube A shows blue – black colour whereas test tube B does not show blue black colour.
Conclusion:
Since test tube B has chewed boiled rice , the saliva present in our mouth acts upon the starch to break it down into sugar. So that is why it does not show any colour in presence of the iodine solution.
On the other hand,boiled rice in test tube A did not come intocontact with saliva(present in our mouth), so starch is present which is indicated by blue-black colour on addition of iodine solution.
Hence we say that the blue black colour signifies the presence of starch in the solution which is not present in the chewed boiled rice and that is why we do not observe any blue black colour and we do not see any colour in presence of Iodine solution.
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