notes on experiment to show that carbon dioxide is necessary for photosynthesis
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To prove that carbon dioxide is released during respiration.
Take a conical flask. Keep some moist cotton and germinated seed in it. Make it air tight by rubbing petroleum jelly. Hand KOH into it and make it air tight. A bent tube is kept here joining the mouth of of conical flask with the beaker full of water.
Here is Potassium Hydroxide absorbs the carbon dioxide which is released by the germinated seed which was kept on the moist cotton then the place become empty therefore vacuum created then vacuum pressure acts and it pulls the water present in beaker through bent tube by which we can observe that carbon dioxide is released by that germinated seed that's why the conical flask becomes vacuum and water is pulled by the bent tube.