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Lewis acid and base example and please use resonate of Lewis structure
Accepted Answer
A classic example of a Lewis acid-base reaction is the reaction between boron trifluoride (BF3) and ammonia (NH3).
BF3 acts as a Lewis acid because it has an incomplete octet on the boron atom, making it electron-deficient. It can accept a pair of electrons from a Lewis base. NH3 acts as a Lewis base because it has a lone pair of electrons on the nitrogen atom, making it electron-rich. It can donate a pair of electrons to a Lewis acid.
The reaction forms a coordinate covalent bond between the boron atom in BF3 and the nitrogen atom in NH3. Here's how the resonance structures would look:
BF3:
The boron atom in BF3 has only 6 valence electrons. To achieve an octet, it can accept a pair of electrons.
NH3:
The nitrogen atom in NH3 has 8 valence electrons and a lone pair of electrons.
The Adduct:
The boron atom in BF3 forms a coordinate covalent bond with the nitrogen atom in NH3. The nitrogen atom donates a pair of electrons to the boron atom. This creates a new adduct molecule, [BF3NH3], with the following resonance structures:
[Image of resonance structures would be here if I could display them. The key is to show the electron pair from N being shared with B and how the negative charge can resonate to the fluorine atoms.]
This adduct is stabilized by the resonance structures that delocalize the negative charge over the fluorine atoms, making the molecule more stable.
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