Real Gas:

Real gases are those gases which do not follow the ideal gas laws under all conditions of temperature and pressure. These gases deviate from ideal gas behaviour due to the intermolecular forces of attraction and repulsion.

Incorrect statement:

The incorrect statement among the given options is option 'C', which states that gases behave as an ideal gas at low pressure and low temperature. This statement is incorrect because real gases do not behave ideally at low pressure and low temperature.

Explanation:

The behaviour of real gases under different conditions of temperature and pressure can be explained using the van der Waals equation. The van der Waals equation is a modified form of the ideal gas equation that includes two corrective factors for intermolecular forces and finite volume of gas particles.

a) Repulsive forces dominate in the low-pressure region:

In the low-pressure region, the intermolecular repulsive forces dominate over the attractive forces, and the gas molecules are far apart from each other. The volume occupied by the gas molecules is negligible compared to the volume of the container. Hence, the gas behaves almost ideally in this region.

b) Volume of gas particles is not negligible in the low-pressure region:

At low pressure, the volume of gas particles becomes significant, and the gas molecules start to occupy more volume than expected. Hence, the gas does not behave ideally in this region.

c) Gas behaves as an ideal gas at low pressure and low temperature:

This statement is incorrect because real gases do not behave ideally at low pressure and low temperature. At low temperatures, the intermolecular forces of attraction become significant, and the gas molecules start to stick together. At low pressures, the volume of gas particles becomes significant, and the gas molecules start to occupy more volume than expected. Hence, the gas does not behave ideally in this region.

d) Attractive forces dominate in the high-pressure region:

In the high-pressure region, the intermolecular attractive forces dominate over the repulsive forces, and the gas molecules come closer to each other. The volume occupied by the gas molecules becomes significant compared to the volume of the container. Hence, the gas does not behave ideally in this region.

Conclusion:

Real gases deviate from ideal gas behaviour due to the intermolecular forces of attraction and repulsion. The behaviour of real gases can be explained using the van der Waals equation. Real gases do not behave ideally at low pressure and low temperature.