During photocatalytic splitting of water, liberation of `O_(2)` requires

Options

A. `Mn^(2+)`
B. `Cl^(-)`
C. `Ca^(2+)`
D. all of these.

Explanation

To answer the question regarding the liberation of O2 during the photocatalytic splitting of water, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Understanding Photolysis of Water**:
- Photolysis refers to the process of breaking down a compound using light. In this case, we are focusing on the photolysis of water (H2O).

2. **Chemical Reaction**:
- The photolysis of water can be represented by the equation:
\[ 2H_2O \rightarrow 4H^+ + 4e^- + O_2 \]
- This indicates that when water is split, it produces protons (H+), electrons (e-), and molecular oxygen (O2).

3. **Role of Light**:
- The process requires light energy (photons) to initiate the breakdown of water molecules.

4. **Oxygen-Evolving Complex**:
- The splitting of water is facilitated by a specific structure known as the oxygen-evolving complex (OEC), which is part of photosystem II in plants.

5. **Components of the Oxygen-Evolving Complex**:
- The OEC consists of several subunits and requires specific ions for its function:
- **Manganese (Mn)**
- **Chloride ions (Cl-)**
- **Calcium ions (Ca2+)**
- **Carbonate ions (CO3^2-)**

6. **Conclusion**:
- Therefore, the liberation of O2 during the photocatalytic splitting of water requires the presence of these ions, making the answer to the question that all of these ions (manganese, chloride, and calcium) are necessary for the process.

### Final Answer:
The liberation of O2 during the photocatalytic splitting of water requires manganese, chloride ions, and calcium ions.

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