The law of partial pressures is most inaccurate when the gases being studied are small medium large

Large

Explanation:

The Law of Partial Pressures, or the Dalton's Law, states that the total pressure of a gas mixture is the sum of the partial pressure of the components, which are the pressure that the substance would have if it was alone in the container.

This law depends on the kinetics of the gas, so it depends on the collisions between the molecules. Small molecules are more suitable at that law because the collision is more effective. As large is the molecule, more inaccurate becomes the law.