Question

Which of the following molecules has the maximum dipole moment?

• A. CH₄
• B. NH₃
• C. NF₃
• D. CO₂

Answer 1

The Correct Option is B

To determine which molecule has the maximum dipole moment among the given options, we need to consider the molecular structure and electronegativity differences within the molecules.

1. Understanding Dipole Moment:
   • Dipole moment is a measure of the separation of positive and negative charges in a molecule. It is calculated as the product of the magnitude of the charge and the distance between the charges.
   • Dipole moment is usually represented by the Greek letter \mu and is measured in Debye units (D).
2. Analyzing Each Molecule:
   1. CH₄ (Methane):
      • The molecule is tetrahedral, and the C-H bond is only slightly polar due to the small electronegativity difference. However, due to the symmetrical shape, the dipoles cancel out, resulting in a net dipole moment of zero.
   2. NH₃ (Ammonia):
      • NH₃ has a trigonal pyramidal shape with a significant net dipole moment. The lone pair on nitrogen causes an asymmetrical charge distribution, leading to a non-zero dipole moment.
   3. NF₃ (Nitrogen Trifluoride):
      • NF₃ also has a trigonal pyramidal shape. However, the electronegativity of fluorine is much higher, which somewhat reduces the net dipole moment compared to NH₃.
   4. CO₂ (Carbon Dioxide):
      • CO₂ is a linear molecule. Even though the C=O bonds are polar, they are in opposite directions and therefore cancel each other out, leading to a zero net dipole moment.
3. Conclusion:
   • The molecule NH₃ has a significant net dipole moment due to its shape and the presence of a lone pair of electrons. Thus, NH₃ has the maximum dipole moment among the given options.