Which type of intermolecular force is predominant in a pure sample of CH\(_3\)OH (methanol)?

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

Answer: (C)

Verified step by step guidance

1. Identify the molecular structure of CH\(_3\)OH (methanol). It consists of a methyl group (CH\(_3\)) attached to a hydroxyl group (OH).
2. Recognize that the OH group contains a highly electronegative oxygen atom bonded to hydrogen, which is a key feature for hydrogen bonding.
3. Recall that hydrogen bonding is a special type of dipole-dipole interaction that occurs when hydrogen is directly bonded to highly electronegative atoms like oxygen, nitrogen, or fluorine.
4. Compare the types of intermolecular forces: ion-dipole forces require ions, which are not present in pure methanol; dipole-dipole forces are present but hydrogen bonding is a stronger specific case; London dispersion forces are present in all molecules but are weaker than hydrogen bonding in this case.
5. Conclude that the predominant intermolecular force in pure CH\(_3\)OH is hydrogen bonding due to the presence of the OH group capable of forming strong hydrogen bonds.