How `NH_(3)` is defined as Lewis base?

Answer

To define how \( \text{NH}_3 \) (ammonia) is classified as a Lewis base, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Definition of Lewis Base**:
A Lewis base is defined as a substance that can donate a pair of electrons to a Lewis acid during a chemical reaction.

2. **Identification of Lone Pair**:
In the case of ammonia (\( \text{NH}_3 \)), the nitrogen atom has a lone pair of electrons. This lone pair is crucial for its behavior as a Lewis base.

3. **Electron Donation**:
When ammonia encounters a Lewis acid (which is an electron pair acceptor), it can donate its lone pair of electrons. This donation forms a coordinate covalent bond between the nitrogen atom of ammonia and the Lewis acid.

4. **Behavior of Ammonia**:
The ability of ammonia to donate its lone pair of electrons allows it to act as a Lewis base. This characteristic is what defines its behavior in chemical reactions.

5. **Conclusion**:
Therefore, ammonia (\( \text{NH}_3 \)) is classified as a Lewis base because it has a lone pair of electrons on the nitrogen atom that it can donate to a Lewis acid.

### Summary:
Ammonia is a Lewis base due to the presence of a lone pair of electrons on the nitrogen atom, which it can donate to a Lewis acid.

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