In photosynthesis , there is

Options

A. Reduction of `H_(2)O`
B. Oxidation of `H_(2)O`
C. Oxidation of `CO_(2)`
D. Oxdiation of `NO_(2)`

Answer

**Step-by-Step Solution:**

1. **Understanding Photosynthesis**: Photosynthesis is the process by which plants produce food using sunlight, carbon dioxide, and water. It occurs mainly in the chloroplasts of plant cells.

2. **Two Main Stages**: Photosynthesis consists of two main stages: the light reactions and the dark reactions (Calvin cycle). The light reactions occur in the thylakoid membranes (grana) of the chloroplasts, while the dark reactions take place in the stroma.

3. **Light Reactions**: During the light reactions, chlorophyll absorbs sunlight. This energy excites electrons, which are then released. The loss of these electrons needs to be compensated.

4. **Photolysis of Water**: To compensate for the lost electrons, water molecules undergo photolysis, which means they are split into hydrogen ions (H⁺), electrons, and oxygen (O₂). The reaction can be summarized as:
\[ 2H_2O \rightarrow 4H^+ + 4e^- + O_2 \]
This process is crucial as it provides the electrons needed to replace those lost by chlorophyll.

5. **Oxidation and Reduction**: In the context of these reactions, when water is split, it loses electrons and is therefore oxidized. Oxidation refers to the loss of electrons, while reduction refers to the gain of electrons.

6. **Evaluating Options**: The question likely presents several options regarding the processes involved in photosynthesis. Based on the explanation:
- **Reduction of H2O**: Incorrect, as water is being oxidized, not reduced.
- **Oxidation of H2O**: Correct, since water loses electrons during photolysis.
- **Oxidation of CO2**: Incorrect, as CO2 is not oxidized in the light reactions.
- **Oxidation of NO2**: Incorrect, as NO2 is not involved in the photosynthesis process.

7. **Conclusion**: The correct answer to the question is the oxidation of H2O.

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