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Question
On a bright sunny day, water weeds growing in an aquarium were actively giving off bubbles of gas. Use this information to answer questions that follow:
- Name the process occurring in the water weed that has resulted in the evolution of these bubbles.
- Of what gas do these bubbles consist?
- Briefly describe the reactions occurring in the leaves of the water weeds leading to the evolution of these bubbles.
- Give an overall balanced chemical equation to represent the process named in (i) above.
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Solution
- Photosynthesis.
- Oxygen.
- The process that takes place first in the photolysis of water is H+ and OH- ions with the help of energy from sunlight. The hydroxyl ions combine to form hydrogen peroxide 2OH —> H2O2 which decompose to give molecular oxygen, i.e.,
2H2O2 ——> 2H2O + O2 - \[\ce{6CO2+12H2O ->[Light][ChlorophyII]C6H12O6+6H2O}\]
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