Which of the following hydrocarbons has the lowest dipole...

Which of the following hydrocarbons has the lowest dipole moment?
(a)
(b) $\mathrm{CH}_{3}-\mathrm{C} \equiv \mathrm{C}-\mathrm{CH}_{3}$
(c) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}=\mathrm{CH}_{2}$
(d) $\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{C} \equiv \mathrm{CH}$

Key Concepts

Bond Polarity

Bond polarity arises from differences in electronegativity between the atoms forming a bond. This polarity contributes to the overall dipole moment of the molecule if the molecular geometry does not allow for cancellation of these bond dipoles. Understanding bond polarity is essential for predicting the directional nature of the dipoles within a molecule.

Electric Dipole Moment

The electric dipole moment is a measure of the separation of electrical charges within a molecule. It is calculated as the vector sum of the individual bond dipoles, and its magnitude provides insight into the overall polarity of the molecule. A molecule with little to no separation of charge will have a low or negligible dipole moment.

Molecular Symmetry

Molecular symmetry plays a crucial role in determining the net dipole moment of a chemical species. In highly symmetrical molecules, individual bond dipoles can cancel each other out, resulting in a low overall dipole moment. Analyzing the symmetry of the molecule helps predict whether the vector sum of the bond dipoles results in a net polarization.

Hybridization and Molecular Geometry

The hybridization state of atoms in a molecule (such as sp, sp2, or sp3) influences both the bond angles and the molecular geometry, which in turn affect the distribution of dipole moments. The spatial arrangement dictated by hybridization can lead to cancellation or reinforcement of individual bond dipoles, impacting the molecule's net polarity.

Transcript

Please give Ace some feedback