The reaction between ammonia (NH₃) and boron trifluoride (BF₃) is a classic example of a Lewis acid-base reaction.
Chemical Equation:
NH₃ + BF₃ → H₃N:BF₃
Explanation:
* Lewis Acid: BF₃ acts as a Lewis acid because it has an incomplete octet in boron and can accept an electron pair. It has a vacant p-orbital on boron.
* Lewis Base: NH₃ acts as a Lewis base because it has a lone pair of electrons on the nitrogen atom. It can donate an electron pair.
Formation of Covalent Bond:
1. Donation: The lone pair of electrons on the nitrogen atom in ammonia is donated to the vacant p-orbital on boron in boron trifluoride.
2. Sharing: The shared electron pair forms a coordinate covalent bond (also called a dative bond) between the nitrogen and boron atoms.
Representation of the Covalent Bond Formation:
The following diagram illustrates the formation of the coordinate covalent bond:
```
H
|
H - N - H + F - B - F
| | |
H F F
↓
H
|
H - N - H → F - B - F
| | |
H F F
|
N → B
```
Conclusion:
The reaction between ammonia and boron trifluoride results in the formation of a coordinate covalent bond between the nitrogen atom of ammonia and the boron atom of boron trifluoride. This is a Lewis acid-base reaction where ammonia acts as a Lewis base donating an electron pair, and boron trifluoride acts as a Lewis acid accepting the electron pair.
