Which of the following halides is inert towards hydrolysis at room temperature ?

Options

A. `SiCl_(4)`
B. `PCl_(3)`
C. `NCl_(3)`
D. `NF_(3)`

Answer

To determine which halide is inert towards hydrolysis at room temperature, we need to analyze the behavior of the given halides when they come into contact with water. Hydrolysis refers to the reaction of a compound with water, leading to the formation of new products.

### Step-by-Step Solution:

1. **Identify the Halides**: We need to consider the halides mentioned in the question. Let's assume the options are NF3, ClF3, SiF4, and PCl5.

2. **Understand Hydrolysis**: Hydrolysis occurs when a compound reacts with water, typically involving the donation of lone pairs from water to the compound. This is more common in compounds that can accommodate additional electrons or have available d-orbitals.

3. **Analyze NF3**:
- NF3 (Nitrogen trifluoride) is composed of nitrogen and fluorine.
- Nitrogen is in the second period and has only p-orbitals available for bonding.
- The fluorine atoms are also in the second period and have fully filled p-orbitals.
- Since both nitrogen and fluorine cannot expand their octets (due to the absence of d-orbitals), NF3 does not undergo hydrolysis at room temperature.

4. **Analyze ClF3**:
- ClF3 (Chlorine trifluoride) contains chlorine, which is in the third period and has d-orbitals available.
- Chlorine can expand its valence shell and accommodate more electrons, allowing it to react with water and undergo hydrolysis.

5. **Analyze SiF4**:
- SiF4 (Silicon tetrafluoride) also contains silicon, which is in the third period and can utilize its d-orbitals for bonding.
- Therefore, SiF4 can undergo hydrolysis as well.

6. **Analyze PCl5**:
- PCl5 (Phosphorus pentachloride) contains phosphorus, which is in the third period and can also expand its valence shell using d-orbitals.
- Hence, PCl5 can undergo hydrolysis.

7. **Conclusion**: Among the given halides, only NF3 is inert towards hydrolysis at room temperature due to the inability of nitrogen and fluorine to expand their octets.

### Final Answer:
The halide that is inert towards hydrolysis at room temperature is **NF3**.