Why does the ideal gas law become less accurate near condensation?

The ideal gas law relies on the assumption that gas molecules move independently, occupy negligible volume, and experience no forces except during brief elastic collisions. These conditions are best met at high temperatures and low pressures, where molecules are far apart and moving too quickly for their interactions to significantly influence their behavior.12

As a gas approaches its condensation point, these assumptions fail. At lower temperatures and higher pressures, molecules are forced closer together, making their individual volumes non-negligible relative to the total space occupied. Furthermore, as molecules slow down and move closer, weak intermolecular forces—such as van der Waals forces—become significant. These attractive forces cause molecules to cohere, which deviates from the ideal model and eventually leads to the gas liquefying.1243