Question

test tube A contains cooked rice and another test tube B contains cooked and chewed rice. what are the changes observed in A and B on adding iodine? why?

Answer 1

cooked rice turns blue
chewed rice doesn't turn blue
this is because cooked rice has carbohydrates and ptylin acts onrice which is chewed and makes it maltose

Answer 2

in test tube B as we chewed the boiled rice the starch present in it breakdown into simple sugar and on adding iodine solution, no colour is changed.
in test A as no saliva is added, on adding iodine solution it turns into blue black colour.