Question

how would you test the presence of starch in boiled rice

Answer 1

Test for presence of starch. Iodinetest is used to test the presence of starch (carbohydrate). Boiled rice and crushed potato contain more amount of starch thereby responding to iodinetest. They develop blue-black colour with iodine.

Answer 2

Put a few drops of Iodine solution in the rice. After some time, it's colour will be changed in blue black colour.

The following activity shows that rice contains starch.

Hope it helps...