Which one of the following conditions are not satisfied by an ideal solution?

A solution M is prepared by mixing ethanol and water. The mole fraction of ethanol in the mixture is $0.9 .$ Given

$\begin{array}{l}{\mathrm{K}}_{\mathrm{f}}\left(\mathrm{Water}\right)=1.86 \mathrm{K} \mathrm{kg} {\mathrm{mol}}^{-1}\\ {\mathrm{K}}_{\mathrm{f}}\left(\mathrm{Ethanol}\right)=2.0 \mathrm{K} \mathrm{kg} {\mathrm{mol}}^{-1}\\ {\mathrm{K}}_{\mathrm{b}}\left(\mathrm{Water}\right)=0.52 \mathrm{K} \mathrm{kg} {\mathrm{mol}}^{-1}\\ {\mathrm{K}}_{\mathrm{b}}\left(\mathrm{Ethanol}\right)=1.2 \mathrm{K} \mathrm{kg} {\mathrm{mol}}^{-1}\end{array}$

Standard freezing point of water $=273\mathrm{K}$

Standard freezing point of ethanol $=155.7 \mathrm{K}$

Standard boiling point of water $=373 \mathrm{K}$

Standard boiling point of ethanol $=351.5 \mathrm{K}$

Vapour pressure of pure water $=32.8 \mathrm{mmHg}$ 

Vapour pressure of pure ethanol $=40 \mathrm{mmHg}$ 

Molecular weight of water $=18 \mathrm{g} {\mathrm{mol}}^{-1}$

Molecular weight of ethanol$=46 \mathrm{g} {\mathrm{mol}}^{-1}$ 

Water is added to the solution M such that the mole fraction of water in solution becomes 0.9. What is the boiling point of this solution?

[Hint: Solute is ethanol and solvent is water]