Which of the following chloride does not react with `PCl_(5)` on heating?

Options

A. `Hg_(2)Cl_(2)`
B. `FeCl_(2)`
C. `S_(2)Cl_(2)`
D. `BC l_(3)`

Answer

To determine which chloride does not react with PCl5 upon heating, we need to analyze the oxidation states of the elements in the chlorides provided and how they interact with phosphorus in PCl5.

### Step-by-Step Solution:

1. **Identify the Chlorides**: List the chlorides provided in the question. For this example, let's assume the chlorides are:
- Hg2Cl2 (Mercury(II) chloride)
- FeCl2 (Iron(II) chloride)
- BCl2 (Boron dichloride)
- Other chloride options (if any).

2. **Determine Oxidation States**: Calculate the oxidation states of the central atoms in each chloride:
- For Hg2Cl2: The oxidation state of mercury (Hg) is +1.
- For FeCl2: The oxidation state of iron (Fe) is +2.
- For BCl2: The oxidation state of boron (B) is +3.

3. **Understand the Reaction with PCl5**: PCl5 has phosphorus in the +5 oxidation state. When a chloride reacts with PCl5, the oxidation state of phosphorus decreases (from +5 to a lower oxidation state), while the oxidation state of the other element typically increases.

4. **Analyze Each Chloride**:
- **Hg2Cl2**: The oxidation state of mercury can increase from +1 to +2 when reacting with PCl5.
- **FeCl2**: The oxidation state of iron can increase from +2 to +3 when reacting with PCl5.
- **BCl2**: The oxidation state of boron cannot increase from +3 to a higher oxidation state (as boron typically does not exceed +3).

5. **Conclusion**: Since BCl2 cannot increase its oxidation state when reacting with PCl5, it does not react upon heating. Therefore, the chloride that does not react with PCl5 on heating is BCl2.

### Final Answer:
The chloride that does not react with PCl5 on heating is **BCl2**.