Question

List out the materials required and the procedure to be followed to prove that "Carbon dioxide is essential for Photosynthesis".

Answer 1

Hint: Photosynthesis is the process by which plants make their food in the presence of sunlight to convert light energy into chemical energy. Oxygen is the byproduct of photosynthesis. Sunlight, water, and carbon dioxide are essential to perform photosynthesis. Photosynthesis gives us oxygen which we need to breathe and we, in turn, exhale carbon dioxide which is needed by the plant.

Complete answer:
The material required for experimenting includes two potted plants, two bell jars, a dropper, a water bath, potassium hydroxide, alcohol, iodine, glass plates. For experimenting with procedure must be followed:
Take two potted plants and keep them in the dark for 24 hours for the removal of starch from the leaves which get used up.
The potted plants are placed on the glass plates and are covered with bell jars.
Put a small amount of anhydrous potassium hydroxide in a petri dish in one bell jar.
Keep this apparatus in sunlight for 4 hours.
Pluck out one leaf from both the plants and boil them in alcohol using a water bath.
Put a few drops of iodine on the leaves for the test of the presence of starch.
This results in turning the leaf into blue colour which shows that the presence of starch takes place when photosynthesis occurs. On the other hand, the leaf taken from the bell jar consists of potassium hydroxide which does not show any blue colour in it due to the presence of no starch as no photosynthesis occurred. It is due to the absorption of carbon dioxide by potassium hydroxide which shows that carbon dioxide is essential for photosynthesis.

Note:
To make one molecule of glucose during photosynthesis it takes 6 molecules of water and six molecules of carbon dioxide. Plants slow the process of photosynthesis during autumn and as a result, leaves change their colour.