Question

When does a gas behave the least like an ideal gas?

• High Pressure and low temperature
• High Pressure and High temperature
• Low Pressure and low temperature
• Low Pressure and High temperature

Solution

An ideal gas follows the equation PV=nRT.

But, to behave like an ideal gas it should satisfy the following:

• There should be no intermolecular forces between the atoms
• The volume occupied by the atoms is neglibile

When we increase the temperature and reduce the pressure, the volume occupied by the atoms becomes negligible compared to the total volume. Secondly at high temperature the kinetic energy of the molecules is so high that work done by the intermolecular forces become neglibile.

For this question we want to find the conditions when it is least likely to satisfy the ideal gas equation and so the answer would be at low temperature and high pressure.