Which of the following molecules exhibits dipole-dipole intermolecular forces?

• A. CH3Cl
• B. CCl4
• C. O2
• D. N2

Answer: (A)

Verified step by step guidance

1. Step 1: Understand that dipole-dipole intermolecular forces occur between molecules that have a permanent dipole moment, meaning the molecule must be polar.
2. Step 2: Analyze the molecular geometry and electronegativity differences in each molecule to determine if it is polar or nonpolar.
3. Step 3: For CH\_3Cl, note that chlorine is more electronegative than carbon and hydrogen, creating an uneven distribution of electron density and a permanent dipole moment, so CH\_3Cl is polar.
4. Step 4: For CCl\_4, although chlorine is electronegative, the molecule is tetrahedral and symmetrical, so the dipoles cancel out, making it nonpolar.
5. Step 5: For O\_2 and N\_2, both are diatomic molecules consisting of identical atoms, so there is no difference in electronegativity and no permanent dipole moment, making them nonpolar.