Which member in each pair has the stronger intermolecular dispersion forces? (c) CH3CH2CH2Cl or (CH3)2CHCl

Verified step by step guidance

1. Identify the type of intermolecular forces present in both molecules. Both CH3CH2CH2Cl and (CH3)2CHCl primarily exhibit dispersion forces (London dispersion forces), which are influenced by the molar mass and shape of the molecule.
2. Compare the molar masses of the two molecules. Generally, a higher molar mass leads to stronger dispersion forces because there are more electrons that can contribute to temporary dipoles.
3. Analyze the molecular shapes and sizes. Molecules with a larger surface area in contact can have stronger dispersion forces because there are more opportunities for temporary dipoles to interact.
4. Consider the branching in the molecules. More branching typically reduces the surface area in contact and can lead to weaker dispersion forces compared to a less branched isomer.
5. Based on the molar mass, molecular shape, and degree of branching, determine which molecule would have the stronger dispersion forces.

Key Concepts

Intermolecular Forces

Intermolecular forces are the forces of attraction or repulsion between molecules. They play a crucial role in determining the physical properties of substances, such as boiling and melting points. The main types of intermolecular forces include hydrogen bonding, dipole-dipole interactions, and dispersion forces, with dispersion forces being the weakest and arising from temporary dipoles in molecules.

Dispersion Forces

Dispersion forces, also known as London dispersion forces, are a type of van der Waals force that occur due to the momentary distribution of electron density in atoms or nonpolar molecules. These forces increase with the size and polarizability of the molecules involved. Larger molecules with more electrons can create stronger temporary dipoles, leading to stronger dispersion forces.

Molecular Structure and Polarity

The molecular structure and polarity of a compound significantly influence its intermolecular forces. In the given compounds, the branching and presence of chlorine affect how closely molecules can pack together and the strength of their dispersion forces. Generally, less branched molecules can have stronger dispersion forces due to a larger surface area for interactions compared to more branched counterparts.