Difference between ideal & ideal-dilute solution

Question

These two terms has been frequently used in Physical Chemistry by Atkins. He describes Raoult's Law using ideal solution while Henry's law using ideal-dilute solution.

I thought, at first they were same but Atkins in order to contrast the two laws presented graphs in which one curve was for ideal solution & another was for ideal-dilute solution. Though he wrote two different sections for these solutions, I really couldn't contrast what the difference actually is between ideal solution & ideal-dilute solution. I googled it but to vain! Can anyone please help what he is trying to say by these two terms?

Answer 1

Raoult's Law is for ideal solutions (all of it: solvent and solute):

Raoult's Law only works for ideal solutions. An ideal solution is defined as one which obeys Raoult's Law. "An ideal solution shows thermodynamic mixing characteristics identical to those of ideal gas mixtures [except] ideal solutions have intermolecular interactions equal to those of the pure components." (all quoted from above link)

As stated here concerning ideal-dilute solutions:

"Many liquid mixtures deviate from the ideal behaviour predicted by Raoult's law. Ideal-dilute solutions are those for which the solvent obeys Raoult's law and the solute Henry's law. The difference in behaviour is because the solvent molecules tend to be surrounded by other solvent molecules so that they behave in an almost ideal way. However, the solute molecules tend also to be surrounded by solvent molecules so that their environment and therefore their thermodynamic behaviour is very unlike that of the pure substance." (all quoted from above link)

In summary: Ideal solutions are those which obey Raoult's Law; ideal-dilute solutions are ones where the solvent obey's Raoult's Law and the solute obeys Henry's Law.