Which is the predominant type of intermolecular force present in CH3OH (methanol)?

• A. London dispersion forces
• B. Ion-dipole interactions
• C. Hydrogen bonding
• D. Dipole-dipole interactions

Answer: (C)

Verified step by step guidance

1. Identify the molecular structure of CH3OH (methanol). It consists of a methyl group (CH3-) attached to a hydroxyl group (-OH).
2. Recognize the types of intermolecular forces possible: London dispersion forces (present in all molecules), dipole-dipole interactions (in polar molecules), ion-dipole interactions (between ions and polar molecules), and hydrogen bonding (a special, strong type of dipole-dipole interaction involving H bonded to N, O, or F).
3. Determine if methanol is polar: The -OH group is highly polar due to the electronegativity difference between oxygen and hydrogen, creating a permanent dipole moment.
4. Check for hydrogen bonding criteria: Methanol has an -OH group where hydrogen is directly bonded to oxygen, which is highly electronegative, allowing for hydrogen bonding between molecules.
5. Conclude that the predominant intermolecular force in CH3OH is hydrogen bonding because it is stronger than London dispersion forces and regular dipole-dipole interactions in this molecule.