Question : Describe an experiment to show that carbon dioxide is essential for photosynthesis .

Question : Describe an experiment to show that carbon dioxide is essen

1.	Question : Describe an experiment to show that carbon dioxide is essential for photosynthesis .
Answer» Solution :(i) Take two healthy potted plants of nearly same size. (ii)Keep them in darkness for THREE days so that all the pre-formed starch is CONSUMED . (iii)Place a watch glass containing POTASSIUM hydroxide by the side of one of the plants. (iv)Cover both the potted plants withseparate bell jarsas shown in the given figure. (v) Usevaselineto seal the bottom of the jars to the glass plate so that the setup is air tight. (vi) Keep the plants in sunglightfor about two hours. (vii)Pluck a leaf from each plant and test for the presence of starch. (viii) The leaf of theplant in setup B keptwithoutpotassium hydroxide will turn blue-black. This confirms the presence of setupformed during photosynthesis. (IX) The leaf of plant in setup A does not show positive test for starch indicating that `CO_(2)`is necessary for photosynthesis. KOH is used to absorb `CO_(2) ` . Dueto non-availability of `CO_(2)`photosynthesis did not occur in setup A .