Arrange He H2 N2 H20 in order of decrease non ideal character?

The non-ideal character of a gas can be determined by its deviation from ideal gas behavior, which is influenced by factors such as molecular size, shape, and intermolecular forces. In general, larger and more polar molecules tend to exhibit greater non-ideal behavior.

Therefore, the order of decrease in non-ideal character for the given gases is as follows:

1. H2 (hydrogen gas) - Hydrogen gas is a small, non-polar molecule with weak intermolecular forces, making it the most ideal gas among the given options.
2. N2 (nitrogen gas) - Nitrogen gas is also a small, non-polar molecule with weak intermolecular forces, but slightly larger than hydrogen, leading to slightly greater non-ideal behavior compared to hydrogen.
3. H2O (water vapor) - Water vapor is a larger, polar molecule with stronger intermolecular forces (hydrogen bonding), leading to greater non-ideal behavior compared to hydrogen and nitrogen gases.

H2 > He > N2 > H20