Question

A green leaf from a mango tree was taken and boiled in water. It was then
boiled in alcohol for few minutes. The leaf was then washed with water and
treated with iodine solution.
i. What is the aim of the activity?
Explain why is the leaf boiled in alcohol?
iii. What colour changes will be observed after adding the iodine solution to
the leaf? What colour changes will be observed if the same activity is
performed with a yellow leaf from a mango plant?

Answer 1

Explanation:

When we boil the leaves in spirit they become colourless because chlorophyll pigments leach out. Leaves contain starch which gives blue-black colour with iodine solution. Starch is synthesised in the green leaves in the presence of sunlight by the process of photosynthesis.

Answer 2

Answer:

1. aim of activity was to test the precense of starch in the leaf. 2. the leaf is boiled in the alcohol to make the leaf colourless.

3. after adding iodine solution the leaf will turn blue - black.