Concept:A coordinate (dative) bond forms when an electron-rich Lewis base donates a lone pair entirely into the empty orbital of an electron-deficient Lewis acid.
Formula:$$ \text{H}_3\text{N}: \longrightarrow \text{BF}_3 $$
Solution:- Ammonia (\( \text{NH}_3 \)) has a complete octet with one non-bonding lone pair on the Nitrogen.
- Boron trifluoride (\( \text{BF}_3 \)) is electron-deficient, having only 6 valence electrons (an incomplete octet).
- Nitrogen donates its lone pair into Boron's empty p-orbital to form the stable \( \text{NH}_3\text{-BF}_3 \) adduct. This specific bond is a coordinate covalent bond.
Why other options are incorrect:- Option A & Option B: These are standard ionic compounds formed by complete electron transfer.
- Option D: Water consists of standard mutual covalent bonds where each atom contributes one electron.
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