Question

The product of pressure and volume (pV) of a gas does not change with volume at a constant temperature only provided that the gas is ideal.

Will the product pV be higher or lower under a very strong compression of a gas if no assumption is made concerning the ideal nature of the gas?

Answer 1

For a very strong compression of the gas, the repulsion among gas molecules becomes significant, and finiteness of their size should be taken into account. This means that other conditions being equal, the pressure of a real gas exceeds the pressure of an ideal gas the stronger, the larger the extent to which the gas is compressed. Therefore, while at a constant temperature the product pV is constant for an ideal gas, it increases with decreasing volume for a real gas.