Which of the following is a polar molecule

Options

A. `SF_4`
B. `SiF_4`
C. `XeF_4`
D. `BF_3`

Answer

To determine which of the given molecules is a polar molecule, we need to analyze each option based on its molecular geometry and dipole moment. A polar molecule has a net dipole moment that is not equal to zero, while a non-polar molecule has a net dipole moment equal to zero.

### Step-by-Step Solution:

1. **Understanding Polar and Non-Polar Molecules**:
- A polar molecule has a net dipole moment (μ) that is not equal to zero. This occurs when there is an uneven distribution of electron density due to differences in electronegativity between atoms.
- A non-polar molecule has a net dipole moment equal to zero, often due to symmetrical geometry that allows dipole moments to cancel each other out.

2. **Analyzing SF4**:
- **Hybridization**: SF4 has sp3d hybridization.
- **Geometry**: The molecular shape is see-saw.
- **Dipole Moment**: The four fluorine atoms create dipole moments directed towards them. Since the geometry is not symmetrical, the dipole moments do not cancel out completely.
- **Conclusion**: SF4 is a polar molecule.

3. **Analyzing SiF4**:
- **Hybridization**: SiF4 has sp3 hybridization.
- **Geometry**: The molecular shape is tetrahedral.
- **Dipole Moment**: In a tetrahedral geometry, the dipole moments from the four fluorine atoms cancel each other out due to symmetry.
- **Conclusion**: SiF4 is a non-polar molecule.

4. **Analyzing XeF4**:
- **Hybridization**: XeF4 has sp3d2 hybridization.
- **Geometry**: The molecular shape is square planar.
- **Dipole Moment**: The dipole moments from the four fluorine atoms cancel each other out due to the symmetrical square planar shape.
- **Conclusion**: XeF4 is a non-polar molecule.

5. **Analyzing BF3**:
- **Hybridization**: BF3 has sp2 hybridization.
- **Geometry**: The molecular shape is trigonal planar.
- **Dipole Moment**: The three fluorine atoms create dipole moments that cancel each other out due to the symmetrical geometry.
- **Conclusion**: BF3 is a non-polar molecule.

### Final Conclusion:
The only molecule among the options that is a polar molecule is **SF4**.

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