Which of the following molecules has polar bonds but is a nonpolar molecule?
Which of the following molecules has polar bonds but is a nonpolar molecule?
NCl3
TeCl4
HF
SF4
XeF4
The Correct Answer and Explanation is :
The correct answer is XeF₄ (Xenon tetrafluoride).
Explanation:
- Polar Bonds vs. Nonpolar Molecules:
- A bond is considered polar if there is a significant difference in electronegativity between the two atoms, resulting in a dipole moment (a separation of charge).
- A molecule is nonpolar overall if the individual dipole moments cancel each other due to the symmetry of the molecule.
- Analysis of Molecules:
- NCl₃: Nitrogen is less electronegative than chlorine, creating polar bonds. However, the molecule is asymmetric due to the lone pair on nitrogen, so it is polar.
- TeCl₄: Tellurium forms polar bonds with chlorine, but the molecule has a seesaw shape (due to one lone pair on Te), making it polar.
- HF: This molecule has only one polar bond and no symmetry to cancel out the dipole, making it polar.
- SF₄: Sulfur forms polar bonds with fluorine, and the molecule adopts a seesaw shape due to one lone pair on sulfur. The asymmetry results in a polar molecule.
- XeF₄: Xenon forms polar bonds with fluorine. However, the molecule has a square planar geometry because of two lone pairs on xenon. The dipole moments of the fluorine atoms cancel out due to this symmetric arrangement, making the molecule nonpolar.
- Why XeF₄ Is Nonpolar:
- The square planar geometry evenly distributes the polar bonds around the xenon atom. The vectors of the individual dipole moments point in opposite directions and cancel out, resulting in no net dipole moment. This makes the molecule nonpolar despite the presence of polar bonds.
- Conclusion:
Among the options, XeF₄ is the only molecule with polar bonds and a nonpolar nature due to its symmetrical geometry.