Which one of the following molecules is polar

Which one of the following molecules is polar? F2

CHBr3

CO2

CBr4

CH4

The correct answer and explanation is :

The correct answer is CHBr3 (tribromomethane).

To explain why, let’s analyze each molecule’s polarity:

1. F2 (Fluorine):

• F2 is a molecule composed of two identical fluorine atoms. Since both atoms have the same electronegativity, there is no difference in electron density between them. This results in a nonpolar molecule because the dipole moments cancel each other out due to the symmetry of the molecule.

1. CHBr3 (Tribromomethane):

• CHBr3 is a tetrahedral molecule where carbon (C) is bonded to three bromine (Br) atoms and one hydrogen (H) atom. In this case, bromine is more electronegative than carbon and hydrogen, which creates polar bonds. The molecule does not have a symmetric arrangement because three bromine atoms are positioned on one side and the hydrogen atom on the opposite side, creating an uneven distribution of charge. The resulting dipoles do not cancel out, making CHBr3 a polar molecule.

1. CO2 (Carbon Dioxide):

• CO2 is a linear molecule with two oxygen (O) atoms double-bonded to a central carbon (C) atom. While each C=O bond is polar due to the difference in electronegativity between carbon and oxygen, the molecule has a linear shape. This symmetry causes the dipole moments to cancel each other out. As a result, CO2 is a nonpolar molecule.

1. CBr4 (Carbon Tetrabromide):

• CBr4 is a tetrahedral molecule where carbon is bonded to four bromine atoms. Although each C-Br bond is polar, the symmetry of the tetrahedral shape causes the dipole moments to cancel each other out, making CBr4 a nonpolar molecule.

1. CH4 (Methane):

• CH4 is a tetrahedral molecule where carbon is bonded to four hydrogen atoms. Since the electronegativity difference between carbon and hydrogen is small, the C-H bonds are only slightly polar. Additionally, the symmetry of the molecule causes the dipole moments to cancel out, making CH4 a nonpolar molecule.

Therefore, the only polar molecule in this list is CHBr3, due to the asymmetrical arrangement of polar bonds that do not cancel out.