Question

Will a leaf taken from a potted plant kept in a dark room for a few days turn blue-black when tested for starch? Give reasons for your answer.

Answer 1

When a potted plant is kept in a dark room for few days, it uses all its starch and due to absence of light, and hence of photosynthesis, there is no starch present in it.
Hence when we test for starch, it gives negative result for starch test and IT DOESNT CHANGE INTO BLUE-BLACK.

Answer 2

NO,it wont whereas ,the leaf exposed to light will turn blue in colour due to presence of starch since iodine reacts with starch to appear blue in colour