Which statement about noble gases is not correct ?

Options

A. a.`Xe` froms `XeF_(6)`
B. b.Ar is used in electric bulbs
C. c.Kr is obtained during radioactive disintegration
D. d.He has the lowest boiling point among all the noble gases

Explanation

To determine which statement about noble gases is not correct, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Analyze the first statement: "Xenon forms XeF6."**
- Xenon (Xe) can react with fluorine (F2) to form xenon hexafluoride (XeF6) when heated. This statement is correct.

2. **Analyze the second statement: "Argon is used in electric bulbs."**
- Argon (Ar) is indeed used in electric bulbs as an inert gas to prevent the filament from oxidizing and burning out quickly. This statement is also correct.

3. **Analyze the third statement: "Helium has the lowest boiling point among all the noble gases."**
- Helium (He) does have the lowest boiling point of all the noble gases due to its small atomic size and weak van der Waals forces. This statement is correct.

4. **Analyze the fourth statement: "Krypton is formed by radioactive disintegration."**
- Krypton (Kr) is not formed by radioactive disintegration. Instead, it is radon (Rn) that is produced through the radioactive decay of radium (Ra). This statement is incorrect.

### Conclusion:
The statement that is not correct is: **"Krypton is formed by radioactive disintegration."**

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