Why NF3 and BiF3 are not hydrolyzed by water?
NF3 and BiF3 are not hydrolyzed by water due to their unique chemical properties. Let's explore the reasons behind this phenomenon.

1. Nature of the bonds
- NF3 and BiF3 have very strong covalent bonds between the nitrogen (N) or bismuth (Bi) atoms and the fluorine (F) atoms. These bonds are not easily broken by water molecules, which are polar and have a tendency to break weaker ionic bonds.
- The strength of the covalent bonds in NF3 and BiF3 makes them resistant to hydrolysis by water.

2. Lewis acidity of nitrogen and bismuth
- Nitrogen in NF3 and bismuth in BiF3 exhibit Lewis acidity, which means they have a tendency to accept electron pairs from other molecules. This makes them less reactive towards water, as they do not readily undergo hydrolysis reactions.
- The Lewis acidity of nitrogen and bismuth in NF3 and BiF3 contributes to their stability in the presence of water.

3. Formation of stable products
- When NF3 or BiF3 come into contact with water, they do not undergo significant hydrolysis reactions. Instead, they may form stable products such as NF3·3H2O and BiO(OH), which do not further react with water.
- The formation of stable products upon interaction with water prevents the complete hydrolysis of NF3 and BiF3.
In conclusion, the strong covalent bonds, Lewis acidity of nitrogen and bismuth, and the formation of stable products contribute to the resistance of NF3 and BiF3 to hydrolysis by water. These factors make NF3 and BiF3 unique compounds that do not undergo significant hydrolysis reactions in aqueous environments.