Which of the following compound cannot be prepared by direct betyween the consituent element?

Options

A. `XeF`
B. `XeO_(3)`
C. `XeF_(4)`
D. `XeO_(2)F_(2)`

Answer

To determine which of the following compounds cannot be prepared by direct reaction between the constituent elements, we need to analyze the formation of various xenon fluorides and oxides.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds in question are xenon fluorides (XeF2, XeF4, XeF6) and xenon oxides (XeO3, XeOF4, XeO2F2).

2. **Direct Preparation of Xenon Fluorides**:
- **XeF2**: Can be prepared by the direct reaction of xenon (Xe) with fluorine (F2).
- **XeF4**: Cannot be prepared directly from xenon and fluorine. It requires a catalyst (nickel) and specific conditions (400°C) for its formation.
- **XeF6**: Can also be prepared by the direct reaction of xenon with fluorine.

3. **Direct Preparation of Xenon Oxides**:
- **XeO3**: This compound is formed from the reaction of xenon fluorides with water, not directly from xenon and oxygen.
- **XeOF4**: This compound is formed from the reaction of XeF6 with water, indicating it cannot be formed directly from xenon and oxygen.
- **XeO2F2**: Similarly, this compound is formed from the reaction of XeOF4 with water.

4. **Conclusion**:
- The compounds that cannot be prepared directly from their constituent elements are **XeF4**, **XeO3**, **XeOF4**, and **XeO2F2**.
- Among the options given, **XeF4** is the most notable as it requires a catalyst and specific conditions for its formation.

### Final Answer:
The compound that cannot be prepared by direct reaction between the constituent elements is **XeF4**.

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