Which of the following compounds will behave least like an ideal gas at low temperatures?

• A. NH_3
• B. N_2
• C. O_2
• D. He

Answer: (A)

Verified step by step guidance

1. Recall that ideal gas behavior assumes no intermolecular forces and that gas particles occupy no volume. Deviations from ideality occur when intermolecular forces become significant, especially at low temperatures.
2. Identify the types of intermolecular forces present in each compound: He is a noble gas with very weak London dispersion forces; N_2 and O_2 are nonpolar diatomic molecules with only London dispersion forces; NH_3 is a polar molecule capable of hydrogen bonding, which is a strong intermolecular force.
3. Understand that stronger intermolecular forces cause gases to deviate more from ideal behavior because these forces affect how molecules attract or repel each other, influencing pressure and volume relationships.
4. At low temperatures, molecules move slower, so intermolecular attractions have a greater effect, making deviations from ideal gas law more pronounced for molecules with stronger forces.
5. Conclude that NH_3, due to its hydrogen bonding and polarity, will behave least like an ideal gas at low temperatures compared to N_2, O_2, and He, which have weaker intermolecular forces.