Assertion. The `HF_(2)^(-)` ion exists in the solid state and also in liquid state but not in aqueous solution.
Reason. The magnitude of hydrogen bonds in between HF-HF molecule is weaker than that in between HF and `H_(2)O` molecules.

Options

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

Explanation

To analyze the assertion and reason provided in the question, we will break down the concepts involved step by step.

### Step 1: Understanding the Assertion
The assertion states that the `HF2^(-)` ion exists in the solid state and liquid state but not in aqueous solution.

**Explanation**:
- The `HF2^(-)` ion is formed by the association of two HF molecules through hydrogen bonding.
- In the solid state, these ions can pack closely together, allowing for stable hydrogen bonding interactions.
- In the liquid state, the ion can still exist due to the presence of strong intermolecular forces.
- However, in aqueous solution, the presence of water molecules may disrupt the hydrogen bonding network between HF molecules, leading to the instability or non-existence of the `HF2^(-)` ion.

### Step 2: Understanding the Reason
The reason provided states that the magnitude of hydrogen bonds between HF-HF molecules is weaker than that between HF and `H2O` molecules.

**Explanation**:
- Hydrogen bonds between HF molecules are indeed strong, but when HF interacts with water, the hydrogen bonding can be even stronger due to the highly polar nature of water.
- Water can stabilize the HF molecules through its own hydrogen bonding, which can lead to the breakdown of the `HF2^(-)` ion in an aqueous environment.

### Step 3: Evaluating the Assertion and Reason
Now, we need to evaluate if the assertion and reason are true or false and if the reason correctly explains the assertion.

1. **Assertion**: True. The `HF2^(-)` ion exists in solid and liquid states but not in aqueous solution.
2. **Reason**: True. The hydrogen bonds between HF and water are stronger than those between HF and HF.
3. **Connection**: The reason does explain why the `HF2^(-)` ion does not exist in aqueous solution, as the stronger hydrogen bonding with water destabilizes the ion.

### Conclusion
Both the assertion and reason are true, and the reason correctly explains the assertion.

### Final Answer
- **Assertion**: True
- **Reason**: True
- **Explanation**: The `HF2^(-)` ion can exist in solid and liquid states due to strong hydrogen bonding between HF molecules, but in aqueous solution, the stronger hydrogen bonding with water destabilizes the ion.

---