Which of the following compounds will have the highest boiling point?

• A. CO_2
• B. H_2O
• C. O_2
• D. CH_4

Answer: (B)

Verified step by step guidance

1. Identify the types of intermolecular forces present in each compound: CO_2, H_2O, O_2, and CH_4. Remember that boiling point is largely influenced by the strength of these forces.
2. For CO_2 and O_2, recognize that these are nonpolar molecules, so their intermolecular forces are primarily London dispersion forces, which are relatively weak.
3. For CH_4, also a nonpolar molecule, the intermolecular forces are London dispersion forces, but consider the molecular size and shape compared to CO_2 and O_2.
4. For H_2O, note that it is a polar molecule capable of hydrogen bonding, which is a much stronger intermolecular force than dispersion forces.
5. Conclude that the compound with hydrogen bonding (H_2O) will have the highest boiling point because stronger intermolecular forces require more energy (higher temperature) to overcome during the phase change from liquid to gas.