Question

The diagram given below represents an experiment to prove the importance of a factor in photosynthesis. Answer the questions that follow:

1. Which factor is being studied here?
2. What is the purpose of keeping KOH in the flask?
3. Explain the term photosynthesis.
4. What will you observe when the leaf A is tested for starch?
5. Write a well balanced chemical equation for the process of photosynthesis.

Answer 1

1. The factor being studied here is the necessity of Carbon dioxide for photosynthesis.
2. KOH absorbs carbon dioxide.
3. Photosynthesis is the process by which living plant cells containing chlorophyll produce food substances (glucose and starch) from carbon dioxide and water using light energy, releasing oxygen as a by-product.
4. The part of the leaf inside the flask will not turn blue, while the part outside the flask will turn blue, showing the presence of starch. This proves that photosynthesis did not occur in the leaf portion inside the flask where carbon dioxide was absent.
5. \[\ce{6CO2 + 12H2O ->[Light energy][Chlorophyll] C6H12O6 + 6H2O + 6O2\uparrow}\]