In which of the following compounds hydrolysis tkes plcae through `S_(N^(1)) and S_(N^(2))` mechanism respectively?

Options

A. `NF_(3), NCl_(3)`
B. `P_(4)O_(10), SiCl_(4)`
C. `SF_(4), TeF_(6)`
D. `SiCl_(4),SiF_(4)`

Answer

To determine which compounds undergo hydrolysis through SN1 and SN2 mechanisms respectively, we need to analyze the nature of the compounds and the conditions under which these mechanisms occur.

### Step 1: Understanding SN1 and SN2 Mechanisms
- **SN1 Mechanism**: This is a two-step reaction where the first step involves the formation of a carbocation intermediate. It typically occurs in polar protic solvents and is favored by tertiary substrates or those that can stabilize a positive charge.
- **SN2 Mechanism**: This is a one-step reaction where the nucleophile attacks the substrate simultaneously as the leaving group departs. It occurs in polar aprotic solvents and is favored by primary substrates or those with less steric hindrance.

### Step 2: Analyzing the Given Compounds
1. **NF3**:
- Nitrogen is bonded to three fluorine atoms. There are no vacant orbitals available for nucleophilic attack, and the molecule is relatively stable. Therefore, it is more likely to undergo hydrolysis through the SN1 mechanism due to the lack of a suitable site for SN2.

2. **NCl3**:
- Similar to NF3, nitrogen is bonded to three chlorine atoms. However, chlorine has a larger atomic radius compared to fluorine, which allows for some steric accessibility. This compound can undergo hydrolysis through the SN2 mechanism due to the presence of a vacant orbital on chlorine, facilitating the nucleophilic attack.

3. **P4O10**:
- Phosphorus in P4O10 has vacant orbitals and can participate in nucleophilic attack. This compound is likely to undergo hydrolysis through the SN2 mechanism.

4. **SiCl4**:
- Silicon in SiCl4 also has vacant orbitals and can undergo nucleophilic attack, making it suitable for the SN2 mechanism as well.

5. **SF4** and **TeF6**:
- Both sulfur and tellurium in these compounds have vacant orbitals and can undergo hydrolysis through the SN2 mechanism.

### Step 3: Conclusion
Based on the analysis:
- **NF3** undergoes hydrolysis via the **SN1 mechanism**.
- **NCl3** undergoes hydrolysis via the **SN2 mechanism**.
- Other compounds like P4O10, SiCl4, SF4, and TeF6 are likely to undergo hydrolysis through the **SN2 mechanism**.

Thus, the correct answer is:
- **NF3 (SN1) and NCl3 (SN2)**.