Which Molecules Will Be Polar Among the Choices?

Which of the molecules below will be polar?

CS2, BF3, SO2, CH3Br

CH3Br only

CS2 only

Both BF3 and CH3Br

Both SO2 and CH3Br

What is a polar molecule?

What are polar and nonpolar molecules?

Answer:

The polar molecules among the given options are SO₂ and CH₃Br.

Among the molecules provided, SO₂ and CH₃Br are polar molecules. CS₂ is nonpolar due to its linear shape, while BF₃ is nonpolar due to its trigonal planar shape with equal bond moments canceling out.

Explanation:

To determine whether a molecule is polar or nonpolar, we consider both the polarity of the individual bonds within the molecule and the overall symmetry of the molecule's shape.

A molecule with high symmetry, like BF₃ which is trigonal planar, will have bond moments that cancel each other out, resulting in a nonpolar molecule. However, molecules with less symmetry, such as SO₂, can exhibit a net dipole moment making them polar.

CS₂ (carbon disulfide) is a linear molecule with bond polarities that cancel out, making it nonpolar. BF₃ (boron trifluoride) is trigonal planar and symmetric, hence nonpolar. On the other hand, SO₂ (sulfur dioxide) is a bent molecule with polar bonds that do not cancel out, so it is polar. CH₃Br (methyl bromide) is a tetrahedral molecule but polar due to the differing electronegativities of hydrogen and bromine.