Which of the following molecules has polar bonds and is nonpolar?

HF
ICI3
NF3
SF4
BF3

Look up the electronegativity of H and F, for example. H is 2.1, F is 4.0, subtract them to get a difference of 1.9 so HF is polar. Strictly speaking, there are no non-polar bonds in those compounds listed. The difference in electronegativity must be zero to have a non-polar bond. ICl3 probably comes the closest to being non-polar but the difference is not zero.

To determine whether a molecule is polar or nonpolar, we need to consider both its molecular geometry and the polarity of its bonds.

Let's go through each of the given molecules to determine if they have polar bonds and if the overall molecule is polar or nonpolar:

1. HF: Hydrogen fluoride (HF) is a polar molecule. The H-F bond is polar because fluorine (F) is more electronegative than hydrogen (H), resulting in partial positive charge on hydrogen and partial negative charge on fluorine. HF has a bent or V-shaped molecular geometry due to its two lone electron pairs on fluorine. Therefore, HF is a polar molecule.

2. ICl3: Iodine trichloride (ICl3) is a polar molecule. The I-Cl bonds are polar because chlorine (Cl) is more electronegative than iodine (I), resulting in partial positive charge on iodine and partial negative charge on chlorine. ICl3 has a trigonal bipyramidal molecular shape due to its three bonded chlorine atoms and two lone pairs on iodine. Therefore, ICl3 is a polar molecule.

3. NF3: Nitrogen trifluoride (NF3) is a polar molecule. The N-F bonds are polar because fluorine (F) is more electronegative than nitrogen (N), resulting in partial positive charge on nitrogen and partial negative charge on fluorine. NF3 has a trigonal pyramidal molecular shape due to its three bonded fluorine atoms and one lone pair on nitrogen. Therefore, NF3 is a polar molecule.

4. SF4: Sulfur tetrafluoride (SF4) is a polar molecule. The S-F bonds are polar because fluorine (F) is more electronegative than sulfur (S), resulting in partial positive charge on sulfur and partial negative charge on fluorine. SF4 has a see-saw molecular shape due to its four bonded fluorine atoms and one lone pair on sulfur. Therefore, SF4 is a polar molecule.

5. BF3: Boron trifluoride (BF3) is a nonpolar molecule. The B-F bonds are polar because fluorine (F) is more electronegative than boron (B), resulting in partial positive charge on boron and partial negative charge on fluorine. However, BF3 has a trigonal planar molecular shape due to its three bonded fluorine atoms and no lone pair on boron. The bond polarities cancel each other out, resulting in a nonpolar molecule.

Therefore, the correct answer is BF3. It has polar bonds but is nonpolar overall.

To determine which of the listed molecules have polar bonds and are nonpolar overall, we need to assess the polarity of each bond within the molecule and consider their molecular geometry.

First, let's identify the polar bonds in the molecules:

- HF: Hydrogen (H) has a significantly lower electronegativity than fluorine (F), so the H-F bond is highly polar.
- ICI3: Chlorine (Cl) has a higher electronegativity than iodine (I), making the individual Cl-I bonds polar.
- NF3: Nitrogen (N) has a higher electronegativity than fluorine (F), causing the N-F bonds to be polar.
- SF4: In this case, sulfur (S) is more electronegative than fluorine (F), so the S-F bonds are polar.
- BF3: Boron (B) has a lower electronegativity than fluorine (F), resulting in nonpolar B-F bonds.

Next, let's consider the molecular geometry of each molecule, as it plays a crucial role in determining overall polarity:

- HF: This molecule has a bent or V-shaped geometry due to two lone pairs on the fluorine atom. The polar H-F bonds do not cancel each other's polarity, resulting in an overall polar molecule.
- ICI3: The central iodine atom in ICI3 has a trigonal bipyramidal geometry, where the three polar Cl-I bonds are inclined to arrange symmetrically. The polarities of the bonds cancel each other out, making the molecule nonpolar.
- NF3: Nitrogen trifluoride has a pyramidal geometry with the lone pair on the nitrogen atom. The polar N-F bonds do not balance each other out due to the pyramid shape, resulting in a polar molecule.
- SF4: The sulfur tetrafluoride molecule has a see-saw or unequal cross shape due to the presence of a lone pair. The polar S-F bonds are not symmetrically arranged, making the molecule overall polar.
- BF3: Boron trifluoride adopts a trigonal planar geometry, with no lone pairs on the central boron atom. The nonpolar B-F bonds and the trigonal planar shape result in a nonpolar molecule.

Therefore, out of the listed molecules, HF and NF3 have polar bonds and are polar overall, while ICI3, SF4, and BF3 have polar bonds but are nonpolar overall.