To determine which molecule is nonpolar, let's analyze the molecular geometry and the distribution of electron pairs around the central atom in each of the listed molecules:
1. NCl[tex]$_3$[/tex] (Nitrogen Trichloride)
- Geometry: Nitrogen in NCl[tex]$_3$[/tex] has three chlorine atoms attached and one lone pair of electrons, resulting in a trigonal pyramidal shape.
- Polar/Nonpolar: The presence of the lone pair on nitrogen introduces an asymmetry to the molecule, causing a net dipole moment. Therefore, NCl[tex]$_3$[/tex] is polar.
2. SCl[tex]$_2$[/tex] (Sulfur Dichloride)
- Geometry: Sulfur in SCl[tex]$_2$[/tex] is bonded to two chlorine atoms with two lone pairs of electrons on sulfur, resulting in a bent shape similar to that of water.
- Polar/Nonpolar: The bent geometry leads to an uneven distribution of charge, creating a dipole moment. As a result, SCl[tex]$_2$[/tex] is polar.
3. OF[tex]$_2$[/tex] (Oxygen Difluoride)
- Geometry: Oxygen in OF[tex]$_2$[/tex] is bonded to two fluorine atoms with two lone pairs of electrons on oxygen, creating a bent molecular shape.
- Polar/Nonpolar: The arrangement causes an uneven distribution of charge, leading to a dipole moment. So, OF[tex]$_2$[/tex] is polar.
4. BF[tex]$_3$[/tex] (Boron Trifluoride)
- Geometry: Boron in BF[tex]$_3$[/tex] is bonded to three fluorine atoms in a trigonal planar structure with no lone pairs on boron.
- Polar/Nonpolar: The trigonal planar shape is symmetrical, and the dipoles of the three B-F bonds cancel each other out, resulting in no net dipole moment. Therefore, BF[tex]$_3$[/tex] is nonpolar.
Given the analysis, the nonpolar molecule is:
BF[tex]$_3$[/tex] (Boron Trifluoride).
