$p_A$ and $p_B$ are the vapour pressure of pure liquid components,$A$ and $B,$ respectively of an ideal binary solution. If $x_A$ represents the mole fraction of component $A,$ the total pressure of the solution will be

Heptane and octane form an ideal solution. At $373 \, K$,the vapour pressures of the two liquid components are $105.2 \, kPa$ and $46.8 \, kPa$ respectively. What will be the vapour pressure of a mixture of $26.0 \, g$ of heptane and $35 \, g$ of octane (in $, kPa$)?

An ideal solution is that which

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 $300 \ K$?

Assertion $A$: For an ideal solution formed by mixing liquids $P$ and $Q$, $\Delta_{mix} H = 0$ and $\Delta_{mix} V = 0$.
Reason $R$: No interactions occur between $P$ and $Q$.
In the light of the above statements, choose the most appropriate answer from the options given below:

For which of the following mixtures is $\Delta_{mix} H > 0$?