Assertion :- The net dipole moment of `BF_3` is zero.
Reason :- The net dipole moment of a molecule depends upon its geometry.

Options

A. If both Assertion and Reason are CORRECT and Reason is the CORRECT explanation of the Assertion
B. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion.
C. If Assertion is CORRECT but Reason is INCORRECT.
D. If Assertion is INCORRECT but Reason is CORRECT.

Answer

To solve the given question regarding the assertion and reason about the net dipole moment of BF3, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the net dipole moment of BF3 is zero.
- To evaluate this, we need to consider the molecular structure and the electronegativity of the atoms involved.

2. **Analyzing the Molecular Geometry**:
- BF3 (Boron Trifluoride) has a trigonal planar geometry.
- In this structure, the boron atom is at the center with three fluorine atoms symmetrically arranged around it.

3. **Electronegativity Consideration**:
- Fluorine is more electronegative than boron, which means that each B-F bond will have a dipole moment pointing towards the fluorine atom.
- However, due to the symmetry of the trigonal planar arrangement, the dipole moments of the three B-F bonds will cancel each other out.

4. **Conclusion on the Assertion**:
- Since the dipole moments cancel each other due to the symmetry of the molecule, the net dipole moment of BF3 is indeed zero.
- Therefore, the assertion is correct.

5. **Understanding the Reason**:
- The reason states that the net dipole moment of a molecule depends upon its geometry.
- This is a true statement because the spatial arrangement of atoms in a molecule affects how the individual dipole moments combine to give a net dipole moment.

6. **Conclusion on the Reason**:
- Since the geometry of BF3 (trigonal planar) leads to the cancellation of dipole moments, the reason is also correct.

7. **Final Evaluation**:
- Both the assertion and the reason are correct, and the reason correctly explains why the assertion is true.

### Final Answer:
Both the assertion and the reason are correct.

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