Question

How does the use of KOH help to show $C{O_2}$ is released during respiration in the germinating seed respiration experiment?

Answer 1

Hint:
For the absorption of $C{O_2}$ from the plant released during respiration, potassium hydroxide is used in the experiment. When $C{O_2}$ is absorbed by KOH, a vacuum is created in the flask. The presence of air in the bent glass tube goes into the conical flask. This further pulls the water in the bent tube.

Complete answer:
Experiment to prove that carbon dioxide gas is produced during the process of respiration in the germinating seeds.
1. Put some of the germinating seeds in a conical flask.
2. The conical flask is fitted to a delivery tube which is bent twice at right angles by the means of cork.
3. Now, suspend a small test tube which contains 20% potassium hydroxide.
4. The free end of the bent tube is then dipped in a beaker containing coloured water.
5. Leave it for almost a day and note the changes in it.
The germinating seeds aerobically respire by utilizing the oxygen in the flask.
6. Potassium hydroxide absorbs the carbon dioxide gas released during the aerobic respiration and it creates a vacuum and causes the water to rise in the bent tube.
7. If a burning candle is introduced in the setup, the candle extinguishes that proves oxygen is utilized for respiration by germinating seed.
The rise in the water level indicates that carbon dioxide gas is released during the process of respiration in the conical flask as a result of germinating gram seeds.

Note: Complete oxidation of carbohydrates takes place during the aerobic respiration. Oxygen breaks the glucose to release energy, while the by-products of the reaction are carbon dioxide and water. This released energy is used to make a special type of energy molecule often named as Adenosine triphosphate (ATP).