Arrange the following compounds in order of increasing boiling point: CH4, NH3, H2O, CO2.

• A. CH4 < NH3 < CO2 < H2O
• B. CO2 < CH4 < NH3 < H2O
• C. CH4 < CO2 < NH3 < H2O
• D. NH3 < CH4 < CO2 < H2O

Answer: (C)

Verified step by step guidance

1. Identify the types of intermolecular forces present in each compound: CH4, NH3, H2O, and CO2. Consider whether they exhibit London dispersion forces, dipole-dipole interactions, or hydrogen bonding.
2. Recall that CH4 (methane) is a nonpolar molecule with only London dispersion forces, which are generally the weakest intermolecular forces.
3. Recognize that CO2 is a linear, nonpolar molecule with London dispersion forces as well, but it has a larger molar mass than CH4, which can increase the strength of dispersion forces and thus the boiling point.
4. Note that NH3 (ammonia) is a polar molecule capable of hydrogen bonding due to the presence of N-H bonds, which significantly increases its boiling point compared to nonpolar molecules.
5. Understand that H2O (water) has strong hydrogen bonding because of its two O-H bonds and bent shape, leading to the highest boiling point among the given compounds.