Which property is not found in an ideal solution?

The boiling point of an equimolar ideal solution of hexane $(C_6H_{14})$ and heptane $(C_7H_{16})$ is $80 \ ^oC$. What is the boiling point of a mixture of hexane and heptane containing equal mass of both? The boiling points of pure hexane and pure heptane are $69 \ ^oC$ and $98 \ ^oC$ respectively.

In a binary ideal solution of liquids $A$ and $B$ at a constant temperature,the mole fraction of $A$ in the liquid phase is $0.7$ and in the vapor phase is $0.4$. If $P_A^o + P_B^o = 90 \, mm$,then the vapor pressures of pure liquids $A$ and $B$ at that temperature are respectively:

At $27^{\circ} C$,two liquids $A$ and $B$ form an ideal solution with mole fractions $0.67$ and $0.33$ respectively. If the vapour pressure of pure $A$ and $B$ at $27^{\circ} C$ are $300 \ mm$ and $450 \ mm$ respectively,the total vapour pressure of the solution in $mm$ is:

Which of the following is not equal to zero for an ideal solution?

Which pair of liquids shows positive deviation from Raoult's law?