Question

Using your knowledge of organic molecules and the following experimental situation answer the next question. Experiment: A cellophane bag is filled with a starch and water. The bag is then immersed in a beaker filled with water and iodine. The bag is permeable to water and iodine but not to starch. When iodine is mixed with starch it turns a blue-black color, where would a color change be detected?
A.Inside the bag

B.Outside the bag

C.Both inside and outside the bag

D.No color change will occur

Answer 1

The answer should be A, inside the bag.

Permeable means allowing certain material to pass through. So if it's permeable to water and iodine, it means it can allow water and iodine to pass through the bag, but doesn't allow starch to go in.

Because iodine can pass through the bag, it can get into the bag filled with starch. But since starch couldn't diffuse out of the bag, the color change is only can be observed inside the bag. When no starch is gone out from the bag, there is no color reaction in the rest of the beaker.

So that answer is A.