Question

Real gases approach ideal gas behaviour at

• A. Low temperature and low pressure
• B. Low temperature and high pressure
• C. High temperature and high pressure
• D. High temperature and low pressure

Answer 1

The correct option is D High temperature and low pressure

Real gases approach ideal gas behaviour at high temperature and low pressure because at high pressures and low temperature, molecules of gases are very close to each other. Molecular interactions start operating. Repulsive forces also become significant. Repulsive interactions are short-range interactions and are significant when molecules are almost in contact and for ideal gas the assumption is that there are negligible attractive forces between gas molecules. Real gases show ideal behaviour when conditions of temperature and pressure are such that the intermolecular forces are practically negligible.This can only happen at very low pressure and very high temperature.