Factors Determining Dipole Moment
The dipole moment of a molecule depends on two main factors: the polarity of the bonds and the molecular geometry. Molecules with polar bonds and an asymmetric arrangement of those bonds tend to have a higher dipole moment.
Analysis of Each Molecule
- CH3Cl
- Bond: Contains one C-Cl bond.
- Geometry: Trigonal pyramidal.
- Dipole Moment: Moderate due to one polar bond.
- CH2Cl2
- Bond: Contains two C-Cl bonds.
- Geometry: Tetrahedral.
- Dipole Moment: Higher than CH3Cl due to two polar bonds, but the bond angles can partially cancel the dipoles.
- CHCl3
- Bond: Contains three C-Cl bonds.
- Geometry: Tetrahedral.
- Dipole Moment: Higher than CH2Cl2, as three polar bonds create a stronger net dipole.
- CCl4
- Bond: Contains four C-Cl bonds.
- Geometry: Tetrahedral.
- Dipole Moment: Zero, because the molecule is symmetrical, and the dipoles cancel each other out.
Conclusion
Among the given options, CHCl3 (chloroform) has the highest dipole moment due to the presence of three C-Cl bonds, which provides a significant net dipole, while maintaining an asymmetric shape that prevents cancellation of the dipoles.
Final Ranking of Dipole Moments
- Highest: CHCl3
- Next: CH2Cl2
- Then: CH3Cl
- Lowest: CCl4 (zero dipole moment)