Which of the following does not undergo Lewis acid-basic reaction?

Options

A. `CO_(2)+H_(2)O`
B. `AlCl_(3)+Cl^(-)`
C. `SF_(6)+BF_(3)`
D. `B(OH)_(3)+H_(2)O`

Answer

To determine which of the given compounds does not undergo a Lewis acid-base reaction, we need to analyze each option based on the definitions of Lewis acids and bases.

### Step-by-Step Solution:

1. **Understanding Lewis Acids and Bases:**
- **Lewis Acid:** An electron-deficient species that can accept an electron pair.
- **Lewis Base:** A species that has a lone pair of electrons and can donate that pair.

2. **Analyzing Each Option:**
- **Option 1: Carbon Dioxide (CO₂) and Water (H₂O)**
- CO₂ has a partial positive charge on carbon and can accept electron pairs, acting as a Lewis acid.
- H₂O has lone pairs on oxygen and can donate them, acting as a Lewis base.
- **Conclusion:** This is a Lewis acid-base reaction.

- **Option 2: Aluminum Chloride (AlCl₃) and Chloride Ion (Cl⁻)**
- AlCl₃ has an incomplete octet and can accept electron pairs, acting as a Lewis acid.
- Cl⁻ has lone pairs and can donate them, acting as a Lewis base.
- **Conclusion:** This is a Lewis acid-base reaction.

- **Option 3: Sulfur Hexafluoride (SF₆) and Boron Trifluoride (BF₃)**
- SF₆ has six bond pairs and does not have lone pairs; it cannot donate electrons, so it cannot act as a Lewis base.
- BF₃ has an incomplete octet and can accept electron pairs, acting as a Lewis acid.
- **Conclusion:** This does not qualify as a Lewis acid-base reaction since there is no Lewis base present.

- **Option 4: Boron Tris(OH)₃ (B(OH)₃) and Water (H₂O)**
- B(OH)₃ has an incomplete octet and can accept electron pairs, acting as a Lewis acid.
- H₂O has lone pairs and can donate them, acting as a Lewis base.
- **Conclusion:** This is a Lewis acid-base reaction.

3. **Final Conclusion:**
- The only pair that does not undergo a Lewis acid-base reaction is **SF₆ and BF₃**, as both can only act as Lewis acids and there is no Lewis base present.

### Answer:
**SF₆ and BF₃ do not undergo a Lewis acid-base reaction.**

---