what is the difference between the real gases and the ideal gases ???

Ideal gases obey the gas law, PV = nRT but real gases do not.

The main difference between real gases and ideal gases lies in their behavior under certain conditions.

Ideal gases are hypothetical gases that perfectly obey the gas laws, including Boyle's law (pressure and volume relationship), Charles's law (volume and temperature relationship), and Avogadro's law (volume and moles relationship). Ideal gases are assumed to have no intermolecular forces and occupy no volume themselves. They also exhibit elastic collisions and experience no attractions or repulsions between gas particles.

On the other hand, real gases deviate from the ideal gas behavior due to the effects of intermolecular forces and finite molecular volumes. These deviations become more prominent at high pressures and low temperatures. Real gases tend to have interactions between their particles, and their volume cannot be neglected. In addition, real gases may condense into liquids or solids when cooled enough or subjected to high pressure.

To determine the difference between a real gas and an ideal gas in practice, one can use the compressibility factor (Z). The compressibility factor accounts for the deviation from ideal gas behavior. For ideal gases, Z is exactly 1, while for real gases, Z deviates from 1.

To experimentally distinguish between real and ideal gases, one must measure the gas's behavior under different temperatures and pressures and analyze the results using equations such as the Van der Waals equation or the Virial equation. These equations incorporate the effect of intermolecular forces and the finite molecular size to account for the deviations from ideal gas behavior.