Which of the following substance can be used for drying neutral or basic gases?

Options

A. `Na_(2)CO_(3)`
B. `CaCO_(3)`
C. `CaO`
D. `Na_(2)CO_(3)`

Explanation

To determine which substance can be used for drying neutral or basic gases, we will analyze the options provided.

### Step-by-Step Solution:

1. **Identify the Options**: The question provides four options, which we need to evaluate to see which can effectively dry neutral or basic gases.

2. **Evaluate Option A: Na2CO3 (Sodium Carbonate)**:
- Sodium carbonate is a basic substance itself.
- Since it is basic, it is not suitable for drying neutral or basic gases as it may react with them.
- **Conclusion**: Na2CO3 is not a drying agent for neutral or basic gases.

3. **Evaluate Option B: CaO (Calcium Oxide)**:
- Calcium oxide is known to be a strong drying agent.
- It can absorb moisture and is effective in drying gases, including neutral and basic gases.
- It reacts chemically to form stable hydroxides, which are non-volatile and can be easily removed.
- **Conclusion**: CaO is a suitable drying agent for neutral or basic gases.

4. **Evaluate Option C: CaCO3 (Calcium Carbonate)**:
- Calcium carbonate is less effective as a drying agent compared to calcium oxide.
- It is not as efficient in removing moisture and does not react in the same way as CaO.
- **Conclusion**: CaCO3 is not suitable for drying neutral or basic gases.

5. **Evaluate Option D**: (Assuming it is another basic substance similar to Na2CO3 or CaCO3).
- Like Na2CO3, if it is also basic, it would not be suitable for drying neutral or basic gases.
- **Conclusion**: This option is also not a suitable drying agent.

### Final Conclusion:
The only substance that can be used for drying neutral or basic gases is **CaO (Calcium Oxide)**.

### Answer:
**C. CaO (Calcium Oxide)**