Assertion (A) : A real gas behaves like ideal gas at low pressure and high temperature.

Reason (R) : At low pressure and high temperature the molecules are far apart and molecular interactions are negligible, without interactions the gas behaves like an ideal gas.

According to kinetic theory of gases, ideal gases have no attractive force between their molecules. The volume occupied by the gas molecules themselves is also considered to be zero. Both these conditions are not true for real gases at normal pressure and temperature. But at low pressure and high temperature, molecules are widely spread and kinetic energy of molecules is very high. These conditions make intermolecular forces negligible. The volume occupied by the molecules themselves is also negligible compared to the volume occupied by the gas. Hence real gas tends to behave as an ideal gas at low pressure and high temperature.