Question

What is the dominant intermolecular force on bond that must be overcome in converting liquid $CH_3 OH$ to a gas?

• A. Hydrogen bonding
• B. Dipole-dipole interaction
• C. Covalent bonds
• D. London or dispersion force

Answer 1

The Correct Option is A

The question asks about the dominant intermolecular force that must be overcome when converting liquid $CH_3OH$ (methanol) to a gas. To determine the correct answer, let's analyze the given options:

1. Hydrogen bonding: Methanol is an alcohol containing an -OH (hydroxyl) group, which enables it to form hydrogen bonds. Hydrogen bonds are strong intermolecular forces that occur when a hydrogen atom covalently bonded to a highly electronegative atom like oxygen, nitrogen, or fluorine is attracted to another electronegative atom. In methanol, hydrogen bonding occurs between the oxygen of one molecule and the hydrogen of another.
2. Dipole-dipole interaction: Methanol molecules can also exhibit dipole-dipole interactions due to their polar nature. However, these forces are generally weaker than hydrogen bonds.
3. Covalent bonds: Covalent bonds are intramolecular forces within a molecule, not intermolecular forces between molecules. Therefore, they are not the force in question when converting methanol to a gas.
4. London or dispersion force: These are weak forces present between all molecules, including non-polar ones. Although present in methanol, they are weaker compared to hydrogen bonds.

Based on the analysis, the most significant intermolecular force in methanol is hydrogen bonding. This is the dominant force that must be overcome during the phase change from liquid to gas, as breaking these forces allows the molecules to separate and enter the gaseous state.

Conclusion: The correct answer is Hydrogen bonding.