In case of Chromatium. H-donor during photosynthesis is

Options

A. `H_2O_2`
B. `H_2S`
C. `H_2O`
D. `H_2SO4`

Answer

To determine the hydrogen donor during photosynthesis in the case of Chromatium, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**: Recognize that the question pertains to Chromatium, specifically Chromatium okenii, which is a type of purple sulfur bacteria.

2. **Understand Photosynthesis Types**: Differentiate between the two main types of photosynthesis: oxygenic and anoxygenic. Oxygenic photosynthesis involves the use of water (H2O) as the electron donor, resulting in the release of oxygen. Anoxygenic photosynthesis does not produce oxygen and uses other compounds as electron donors.

3. **Determine the Photosynthetic Process in Chromatium**: Research indicates that Chromatium performs anoxygenic photosynthesis. This means it does not release oxygen during the process.

4. **Identify the Electron Donor**: In anoxygenic photosynthesis, Chromatium uses hydrogen sulfide (H2S) as the electron donor instead of water. This is a key characteristic of this type of bacteria.

5. **Evaluate the Options**:
- Hydrogen peroxide (H2O2) is not used as a hydrogen donor in photosynthesis.
- Hydrogen sulfide (H2S) is indeed the correct answer as it is used by Chromatium.
- Water (H2O) is typically used in oxygenic photosynthesis, not in the case of Chromatium.
- Sulfuric acid (H2SO4) does not play a role in photosynthesis for Chromatium.

6. **Conclusion**: Based on the analysis, the correct answer is hydrogen sulfide (H2S).

### Final Answer:
The hydrogen donor during photosynthesis in the case of Chromatium is **hydrogen sulfide (H2S)**.

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