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AimThe objective of this experiment is to demonstrate that carbon dioxide is released during the process of respiration.
Apparatus RequiredSoaked gram seeds
U-shaped delivery tube
Conical flask
Blotting paper (moist) /cotton wool
Test tube
Rubber cork with a single hole
Freshly prepared KOH solution (20%)
TheoryRespiration is a catabolic biochemical process that involves the oxidation of food (glucose) to release energy.
For this experiment, moist gram seeds are used because they are actively respiring and releasing CO2. The CO2 that is released is absorbed by KOH, forming K2CO3.
KOH is used in the experiment to absorb the CO2 released during respiration by the moist gram seeds. The reaction between the two produces K2CO3 and H2O.
2KOH + CO2 ⟶ K2CO3 + H2O)
Prosedure1 .Begin by germinating around 25 seeds, which can be achieved by wrapping them in moist blotting paper or cotton wool for 3-4 days.
2 .Once the seeds have germinated, place them in a conical flask and dampen them with a spray of water.
3 .Suspend the conical flask, along with a test tube containing freshly prepared 20% KOH solution, using a thread.
4 .Use a rubber cork to seal the opening of the conical flask.
5 .Insert one end of a U-shaped glass delivery tube into the hole in the rubber cork and place the other end in a beaker filled with water.
6 .Seal all connections in the setup using vaseline to create an airtight environment.
7 .Mark the initial water level in the U-shaped delivery tube.
8 .Leave the experimental setup undisturbed for 1-2 hours and observe any changes in the water level in the tube.
Result and observationThe temperature inside the container should have increased slightly due to the heat released during respiration.
The limewater solution may turn cloudy, indicating the presence of carbon dioxide.
The mass of the seeds should have decreased slightly due to the release of carbon dioxide during respiration.

Based on the results of this experiment, we can conclude that carbon dioxide is released during the process of respiration. This is demonstrated by the presence of cloudy limewater solution and the decrease in seed mass, which indicates the release of carbon dioxide.