For a solution of two liquids $A$ and $B$,if $P = X_A (P_A^o - P_B^o) + P_B^o$ holds true,then what type of solution is it?

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 $300 \ K$?

Which from the following liquid mixtures behaves nearly as an ideal solution?

Which of the following does not show negative deviation from Raoult's law?

Which of the following mixtures does not show positive deviation from Raoult's law?

Which of the following liquid pairs does not show contraction in volume on mixing?