$A$ liquid mixture is an ideal solution,if
$(I)$ It obeys ideal gas equation
$(II)$ It obeys Raoult's law at all concentrations
$(III)$ Solute - solute,solute - solvent and solvent - solvent interactions are similar

At $300 \ K$,the vapour pressure of a pure liquid $A$ is $70 \ mm \ Hg$. It forms an ideal solution with another liquid $B$. The mole fraction of $B$ in the solution is $0.2$ and the total vapour pressure of the solution is $84 \ mm \ Hg$ at the same temperature. What is the vapour pressure (in $mm \ Hg$) of pure liquid $B$ at $300 \ K$?

Liquids $A$ and $B$ form an ideal solution. Which of the following statements is true?

$A$ mixture of toluene and benzene forms a nearly ideal solution. Assume $p_{B}^{\circ}$ and $p_{T}^{\circ}$ to be the vapour pressures of pure benzene and toluene,respectively. The slope of the line obtained by plotting the total vapour pressure versus the mole fraction of benzene is $....$

An example of a near-ideal solution is:

Each pair forms an ideal solution except?