In the activity to demonstrate that chlorophyll is essential for photosynthesis, a plotted plant with variegated leaves is first taken and kept in a dark room for three days after which it is kept in sunlight for about six hours. The leaf is then plucked, the green areas traced and then the leaf is first dipped in boiling water for a few minutes and then immersed in a beaker containing alcohol as shown in diagram below:

The reason why leaf is immersed in hot alcohol is to:

Options

A. remove chlorophyll
B. stop photosynthesis
C. dissolve starch
D. dissolve phloem

Answer

A

Explanation

We boil the leaf in alcohol when We are testing it for starch to remove the green pigment chlorophyll present in it. For the starch test, we need to observe the colour change from brown to blue when iodine is put on the lea£ But, as the leaf is green in colour it does not show the required observation. Hence to remove the green pigment present in the leaf we boil the leaf in alcohol when we are testing it for starch.