Which of the following is a non-ideal solution?

At $27^o C$,the vapor pressure of pure liquid $A$ is $70 \ torr$. It forms an ideal solution with $B$. The mole fraction of $B$ is $0.2$ and the vapor pressure of the solution at $27^o C$ is $84 \ torr$. What is the vapor pressure of pure liquid $B$ at $27^o C$ (in $torr$)?

$A$ liquid solution is formed by mixing $10 \, moles$ of aniline and $20 \, moles$ of phenol at a temperature where the vapour pressure of pure liquid aniline and phenol are $90 \, mmHg$ and $87 \, mmHg$ respectively. The possible vapour pressure of the solution at that temperature is ............. $mmHg$.

$A$ solution of acetone in ethanol:

Two statements are given below:
Statement-$I$: Liquids $A$ and $B$ form a non-ideal solution with positive deviation. The interactions between $A$ and $B$ are weaker than $A-A$ and $B-B$ interactions.
Statement-$II$: For an ideal solution,$\Delta_{mix} H = 0$ and $\Delta_{mix} V = 0$.
The correct answer is:

Mixing $1 \ mol$ of heptane $(V.P = 92 \ mm \ Hg)$ with $4 \ mol$ of octane $(V.P = 31 \ mm \ Hg)$ forms an ideal solution. The vapor pressure of the solution will be .......... $mm \ Hg$. (in $.2$)