Question

Q8. Some crushed boiled rice is put in water in a test tube and a few drops of dilute
iodine solution are added to it. A blue black colour is produced which shows the
presence of X'in rice. If, however, the crushed boiled rice and water are first warmed
with saliva for some time and then dilute iodine solution is added, then no blue-black
colour is produced. This shows that saliva converts X'into product Y' which does not
produce blue-black colour with diluteiodine solution.
(a) Name (i) 'X' and (ii) 'Y
(b) What does the above activity tell us about the role of saliva in the digestion of food.​

Answer 1

Answer:

a)(i) Starch

(ii) A sugar (Maltose)

b)Saliva helps in digesting starch carbohydrate present in food.

Explanation:

Answer 2

Answer:

A few drops of iodine solution were added to rice water the solution turned blue black in Colour This indicates that rice water contain

Leaves contain starch which gives blue-black colour with iodine solution. Starch is synthesised in the green leaves in the presence of sunlight by the process of photosynthesis. Starch gets stored in leaves or gets transported to other parts of the plant.