Question

Which is stronger, a dipole-dipole attraction between two molecules or a covalent bond between two atoms within the same molecule? Explain.

Short answer

A covalent bond between two atoms within the same molecule is stronger than a dipole-dipole attraction between two molecules. This is because covalent bonds involve sharing of electrons, creating strong intramolecular forces, whereas dipole-dipole attractions are weaker intermolecular forces occurring due to electrostatic attraction between polar molecules.

Step-by-step solution

Understanding Dipole-Dipole Attractions and Covalent Bonds

Dipole-dipole attractions occur between polar molecules. Polar molecules have a difference in electronegativity between the atoms in the molecule, leading to an uneven distribution of electron density and thus creating positive and negative poles within the molecule. These polar molecules are attracted to each other due to the electrostatic attraction between their positive and negative poles. Covalent bonds, on the other hand, involve sharing of electrons between two atoms. The atoms involved in a covalent bond share their valence electrons to achieve stability and lower the potential energy between them. Covalent bonding is a strong chemical bond as it involves forming a stable electron configuration within a molecule.

Comparing the Strengths of Dipole-Dipole Attractions and Covalent Bonds

When comparing the strength of dipole-dipole attraction and covalent bonds, it is essential to consider the forces involved and the energy required to break these interactions. Dipole-dipole attractions are intermolecular forces, meaning they occur between separate molecules. These attractions, while significant in determining properties of substances like boiling points and melting points, are relatively weak when compared to covalent bonds. Covalent bonds are intramolecular forces, meaning they occur within a single molecule and hold the atoms together. Due to the sharing of electrons between atoms, covalent bonds are much stronger than dipole-dipole interactions. A greater amount of energy is required to break these bonds, making them more stable and robust than dipole-dipole attractions.

Conclusion

A covalent bond between two atoms within the same molecule is stronger than a dipole-dipole attraction between two molecules. The covalent bond involves sharing of electrons between atoms, creating an intramolecular force that is much stronger than the intermolecular forces in a dipole-dipole attraction.