Biology, asked by abhirajratna, 3 months ago

In the activities related to photosynthesis, the leaf is boiled in water and then in alcohol. answer the following questions
[i] Why does the colour of alcohol turn green though the colour of water does not change?
[ii] How is the manner of heating of water-container and alcohol-container different? Why?
[iii] How does iodine test help us to reach conclusions?

Answers

Answered by Anonymous
4

Answer:

  1. The hot water kills the leaf and the alcohol breaks down the chlorophyll, taking the green color out of the leaf
  2. Alcohol is highly inflammable and its vapors are explosive, therefore, limiting heat applies becomes necessary. The bath with the boiling water produces a constant temperature of just a few degrees over the boiling point of the isopropyl alcohol, so to restrict boiling of the alcohol to a sustained rate.
  3. Iodine is an indicator that turns blue-black in the presence of starch. The leaf that was in the light turns blue-black, which demonstrates that the leaf has been performing photosynthesis and producing starch. Try the test again with a variegated leaf (one with both green and white) that has been in the sunlight.

thank you

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