Which of the following substances has dispersion forces as its only intermolecular force?

• A. CH3Cl (chloromethane)
• B. Ne (neon)
• C. HCl (hydrogen chloride)
• D. NH3 (ammonia)

Answer: (B)

Verified step by step guidance

1. Identify the types of intermolecular forces present in each substance. The main types are dispersion forces (London forces), dipole-dipole interactions, and hydrogen bonding.
2. Recall that dispersion forces are present in all molecules but are the only intermolecular force in nonpolar molecules or atoms.
3. Analyze each substance: CH3Cl is polar due to the C-Cl bond, so it has dipole-dipole forces and dispersion forces; HCl is polar, so it has dipole-dipole and dispersion forces; NH3 has N-H bonds and a lone pair on nitrogen, enabling hydrogen bonding in addition to dipole-dipole and dispersion forces.
4. Neon (Ne) is a noble gas atom, nonpolar and monatomic, so it only exhibits dispersion forces as its intermolecular force.
5. Conclude that the substance with only dispersion forces is Ne (neon), because it is nonpolar and monatomic, lacking dipole moments or hydrogen bonding capability.