Which of the following species can acts as bronsted base as well as a Lewis base?

Options

A. `NO_(3)^(-)`,
B. `CN^(-)`
C. `NH_(3)`
D. `BF_(3)`

Answer

To determine which species can act as both a Brønsted base and a Lewis base, we need to analyze each option given in the question.

### Step-by-Step Solution:

1. **Understand Brønsted and Lewis Bases**:
- A **Brønsted base** is a species that can accept a proton (H⁺).
- A **Lewis base** is a species that can donate an electron pair.

2. **Evaluate Each Species**:
- **Option 1: NO3⁻ (Nitrate ion)**:
- *Brønsted Base*: NO3⁻ can accept a proton (H⁺) to form HNO3 (nitric acid). Thus, it acts as a Brønsted base.
- *Lewis Base*: NO3⁻ can donate an electron pair to form a bond with H⁺. Therefore, it also acts as a Lewis base.
- Conclusion: NO3⁻ acts as both a Brønsted base and a Lewis base.

- **Option 2: CN⁻ (Cyanide ion)**:
- *Brønsted Base*: CN⁻ can accept a proton (H⁺) to form HCN (hydrogen cyanide). Thus, it acts as a Brønsted base.
- *Lewis Base*: CN⁻ can donate an electron pair to H⁺, forming a bond. Therefore, it also acts as a Lewis base.
- Conclusion: CN⁻ acts as both a Brønsted base and a Lewis base.

- **Option 3: NH3 (Ammonia)**:
- *Brønsted Base*: NH3 can accept a proton (H⁺) to form NH4⁺ (ammonium ion). Thus, it acts as a Brønsted base.
- *Lewis Base*: NH3 has a lone pair of electrons on nitrogen, which it can donate to H⁺ to form a bond. Therefore, it also acts as a Lewis base.
- Conclusion: NH3 acts as both a Brønsted base and a Lewis base.

- **Option 4: BF3 (Boron trifluoride)**:
- *Brønsted Base*: BF3 cannot accept a proton because it is electron deficient and does not have available electrons to bond with H⁺. Therefore, it does not act as a Brønsted base.
- *Lewis Base*: BF3 can accept an electron pair due to its electron deficiency, which allows it to act as a Lewis acid, but not a Lewis base.
- Conclusion: BF3 does not act as a Brønsted base or a Lewis base.

3. **Final Conclusion**:
- The species that can act as both a Brønsted base and a Lewis base are: **NO3⁻, CN⁻, and NH3**.

### Answer:
The correct options are 1 (NO3⁻), 2 (CN⁻), and 3 (NH3).

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