In a pure sample of CH4, what types of intermolecular forces exist between the molecules?

• A. Dipole-dipole forces only
• B. Both dipole-dipole forces and hydrogen bonding
• C. London dispersion forces only
• D. Hydrogen bonding only

Answer: (C)

Verified step by step guidance

1. Identify the molecular structure of CH4 (methane). It consists of one carbon atom bonded to four hydrogen atoms in a tetrahedral geometry.
2. Determine the polarity of the CH4 molecule. Since the C-H bonds have very similar electronegativities and the molecule is symmetrical, CH4 is nonpolar overall.
3. Recall that nonpolar molecules do not have permanent dipole moments, so dipole-dipole interactions and hydrogen bonding are not possible.
4. Understand that all molecules, including nonpolar ones like CH4, exhibit London dispersion forces (also called induced dipole-induced dipole interactions), which arise from temporary fluctuations in electron distribution.
5. Conclude that the only intermolecular forces present between CH4 molecules are London dispersion forces.