Statement-1 : `AlF_(3)` is a high melting point solid whereas `SiF_(4)` is a gas
and
Statement-2 : Both `AlF_(3)` and `SiF_(4)` are covalent molecules .

Options

A. Statement-1 is True , Statement-2 is True , Statement-2 is a correct explanation for Statement-1
B. Statement-1 is True , Statement-2 is True , Statement-2 is NOT a correct explanation for Statement-1
C. Statement-1 is True , Statement-2 is False
D. Statement-1 is False , Statement-2 is True

Answer

To analyze the statements provided in the question, we will evaluate each statement separately and determine their validity.

### Step 1: Analyze Statement-1
**Statement-1:** AlF₃ is a high melting point solid whereas SiF₄ is a gas.

- **AlF₃ (Aluminum Fluoride):**
- AlF₃ has a high melting point due to its ionic nature. Aluminum (Al) has a significant electronegativity difference with fluorine (F), leading to the formation of ionic bonds. Ionic compounds typically have high melting and boiling points due to the strong electrostatic forces between the positively charged aluminum ions and negatively charged fluoride ions.

- **SiF₄ (Silicon Tetrafluoride):**
- SiF₄, on the other hand, is a covalent molecule. Silicon (Si) and fluorine (F) have a smaller electronegativity difference compared to aluminum and fluorine, resulting in covalent bonding. Covalent compounds generally have lower melting and boiling points, and SiF₄ exists as a gas at room temperature.

**Conclusion for Statement-1:** This statement is true.

### Step 2: Analyze Statement-2
**Statement-2:** Both AlF₃ and SiF₄ are covalent molecules.

- **AlF₃:** As established earlier, AlF₃ is primarily ionic due to the high electronegativity difference between aluminum and fluorine. Therefore, it cannot be classified as a covalent molecule.

- **SiF₄:** This molecule is indeed covalent, as discussed, due to the smaller electronegativity difference between silicon and fluorine.

**Conclusion for Statement-2:** This statement is false because AlF₃ is not a covalent molecule.

### Final Conclusion
- **Statement-1 is true.**
- **Statement-2 is false.**

Thus, the correct answer is that Statement-1 is true and Statement-2 is false.