Assertion:`PCl_(5)` is covalent in gaseous and liquid states but ionic in solid state.
Reason: `PCl_(5)` in solid state consits of tetrahhedral `PCl_(4)^(+)` cation and octahedral `PCl_(6)^(-)` anion.

Options

A. (a) Statement-1 is true, statement-2 is true, statement-2 is a correct explanation for statement-1
B. (b) Statement-1 is true, statement-2 is true, statement-2 is not correct explanation for statement-1
C. (c) Statement-1 is true, statement-2 is false
D. (d) Statement-1 is false, statement-2 is true

Answer

To solve the question, we need to analyze the assertion and reason provided regarding phosphorus pentachloride (PCl₅).

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that PCl₅ is covalent in the gaseous and liquid states but ionic in the solid state.
- In the gaseous and liquid states, PCl₅ exists as a covalent molecule. This is due to the sharing of electrons between phosphorus and chlorine atoms.

**Hint**: Think about the nature of bonding in different states of matter.

2. **Analyzing the Bonding in PCl₅**:
- Phosphorus (P) has five valence electrons and can form five covalent bonds with chlorine (Cl) atoms.
- In the gaseous and liquid states, PCl₅ adopts a triangular bipyramidal geometry due to sp³d hybridization, indicating covalent bonding.

**Hint**: Recall the hybridization and molecular geometry of PCl₅.

3. **Understanding the Ionic Nature in Solid State**:
- The reason states that in the solid state, PCl₅ consists of a tetrahedral PCl₄⁺ cation and an octahedral PCl₆⁻ anion.
- In the solid state, PCl₅ can dissociate into these ions, indicating an ionic structure.

**Hint**: Consider how molecules behave when they transition from gaseous to solid states, especially in terms of ion formation.

4. **Evaluating the Reason**:
- The reason provided is true because PCl₄⁺ and PCl₆⁻ indeed represent the ionic form of PCl₅ in the solid state.
- The tetrahedral shape of PCl₄⁺ and octahedral shape of PCl₆⁻ supports the assertion that PCl₅ is ionic in solid form.

**Hint**: Visualize the structures of the ions to understand their shapes and charges.

5. **Conclusion**:
- Both the assertion and reason are true, and the reason correctly explains the assertion.
- Therefore, the correct answer is that both statements are true, and the reason is the correct explanation for the assertion.

### Final Answer:
**Option A**: Statement 1 is true, statement 2 is true, and statement 2 is the correct explanation for statement 1.