Assertion(A): Fluorine exists only in `-1` oxidation state.
Reason(R): Fluorine has `2s^(2)2p^(5)`configuration.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explantion of the assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Fluorine exists only in -1 oxidation state."
- Fluorine is the most electronegative element and tends to gain one electron to achieve a stable electronic configuration (octet).
- In all its compounds, fluorine is found in the -1 oxidation state, such as in HF, NaF, etc.
- Therefore, the assertion is **true**.

2. **Understanding the Reason (R)**:
- The reason states that "Fluorine has a 2s² 2p⁵ configuration."
- The electronic configuration of fluorine is indeed 1s² 2s² 2p⁵.
- This configuration indicates that fluorine has 7 electrons in its outer shell and needs one more electron to complete its octet.
- Thus, the reason is also **true**.

3. **Analyzing the Relationship**:
- While both the assertion and the reason are true, the reason does not logically explain why fluorine only exists in the -1 oxidation state.
- The assertion is based on fluorine's high electronegativity and its tendency to gain one electron, which is not directly explained by the electronic configuration alone.
- Therefore, the reason is not the correct explanation for the assertion.

4. **Final Conclusion**:
- Both the assertion and reason are true, but the reason does not correctly explain the assertion.
- Hence, the answer is **B**: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.