Which of the following compounds are acidic?

Options

A. `B(OH)_(3)`
B. `Al(OH)_(3)`
C. `BF_(3)`
D. `CO_(2)`

Answer

To determine which of the given compounds are acidic, we will analyze each compound based on its chemical properties and behavior in water.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds provided are:
- BOH₃ (Boric acid)
- Al(OH)₃ (Aluminum hydroxide)
- BF₃ (Boron trifluoride)
- CO₂ (Carbon dioxide)

2. **Analyze BOH₃**:
- **Dissolution in Water**: When BOH₃ (boric acid) dissolves in water, it forms H₃BO₃, which is known to exhibit acidic properties.
- **Conclusion**: BOH₃ is acidic.

3. **Analyze Al(OH)₃**:
- **Dissolution in Water**: Al(OH)₃ (aluminum hydroxide) contains hydroxyl ions (OH⁻). It does not produce H⁺ ions when dissolved in water.
- **Conclusion**: Al(OH)₃ is a base, not acidic.

4. **Analyze BF₃**:
- **Dissolution in Water**: BF₃ (boron trifluoride) reacts with water to produce H₃BO₃ (boric acid) and HF (hydrofluoric acid). Since it forms acids upon reaction with water, it is considered acidic.
- **Conclusion**: BF₃ is acidic.

5. **Analyze CO₂**:
- **Dissolution in Water**: CO₂ (carbon dioxide) reacts with water to form H₂CO₃ (carbonic acid). This indicates that CO₂ exhibits acidic behavior.
- **Conclusion**: CO₂ is acidic.

### Final Summary:
- **Acidic Compounds**: BOH₃, BF₃, CO₂
- **Non-Acidic Compound**: Al(OH)₃