The noble gas used in the preperation of first noble gas compound was?

Options

A. Xe
B. He
C. Cr
D. Rn

Answer

To solve the question regarding which noble gas was used in the preparation of the first noble gas compound, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Noble Gases**: The noble gases mentioned are xenon, helium, chromium, and radon. However, chromium is not a noble gas; it is a transition metal. The relevant noble gases here are xenon and radon.

2. **Historical Context**: The first noble gas compound was synthesized by a scientist named Neil Bartlett. It is important to note the contributions of scientists in the field of chemistry.

3. **Understanding the Experiment**: Neil Bartlett observed the reaction of noble gases with other elements. He initially created a compound involving molecular oxygen and platinum hexafluoride (O2^+ and PtF6^-).

4. **Ionization Energies**: Bartlett noted that the first ionization energy of xenon (Xe) is similar to that of molecular oxygen (O2). Specifically, the ionization enthalpy of O2 is approximately 1175 kJ/mol, while that of xenon is about 1170 kJ/mol.

5. **Substituting Xenon**: Based on the similarity in ionization energies, Bartlett hypothesized that if a compound could be formed with O2, a similar compound could be formed using xenon. He successfully synthesized the compound Xe^+ and PtF6^-.

6. **Conclusion**: Therefore, the noble gas used in the preparation of the first noble gas compound was **xenon**.

### Final Answer:
The noble gas used in the preparation of the first noble gas compound was **xenon**.

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