The fluoride for which the dipole moment is not equal to zero, is :

Options

A. `XeF_(4)`
B. `CF_(4)`
C. `SF_(4)`
D. `PF_(5)`

Answer

To determine which fluoride has a non-zero dipole moment, we will analyze the molecular geometry and the presence of lone pairs for each of the given options.

### Step-by-Step Solution:

1. **Understanding Dipole Moment**:
- The dipole moment is a vector quantity that depends on the difference in electronegativity between atoms and the geometry of the molecule. A molecule has a non-zero dipole moment if the bond dipoles do not cancel out completely.

2. **Analyzing the First Option: Xenon Tetrafluoride (XeF4)**:
- Xenon (Xe) has 8 valence electrons. In XeF4, it forms 4 bonds with fluorine (F), using 4 of its electrons, leaving 4 electrons which form 2 lone pairs.
- The molecular geometry is square planar due to the presence of 2 lone pairs.
- The bond dipoles from the Xe-F bonds cancel each other out because of the symmetry of the square planar shape.
- **Conclusion**: XeF4 has a dipole moment of zero.

3. **Analyzing the Second Option: Carbon Tetrafluoride (CF4)**:
- Carbon (C) has 4 valence electrons and forms 4 bonds with fluorine, using all its electrons.
- The molecular geometry is tetrahedral.
- The bond dipoles from the C-F bonds also cancel each other out due to the symmetry of the tetrahedral shape.
- **Conclusion**: CF4 has a dipole moment of zero.

4. **Analyzing the Third Option: Sulfur Tetrafluoride (SF4)**:
- Sulfur (S) has 6 valence electrons. In SF4, it forms 4 bonds with fluorine, using 4 electrons, leaving 2 electrons which form 1 lone pair.
- The molecular geometry is see-saw due to the presence of one lone pair.
- The bond dipoles from the S-F bonds do not cancel out completely because of the asymmetrical shape created by the lone pair.
- **Conclusion**: SF4 has a non-zero dipole moment.

5. **Analyzing the Fourth Option: Phosphorus Pentafluoride (PF5)**:
- Phosphorus (P) has 5 valence electrons and forms 5 bonds with fluorine, using all its electrons.
- The molecular geometry is trigonal bipyramidal.
- The bond dipoles from the P-F bonds cancel each other out due to the symmetry of the trigonal bipyramidal shape.
- **Conclusion**: PF5 has a dipole moment of zero.

### Final Answer:
The fluoride with a non-zero dipole moment is **SF4**.