Which property is shown by an ideal solution?

The liquid pair benzene-toluene shows

Determination of correct molecular mass from Raoult's law is applicable to

At $373 \ K$,heptane and octane form an ideal solution. The vapor pressures of the two pure liquid components (heptane and octane) are $105 \ kPa$ and $45 \ kPa$,respectively. The vapor pressure of the solution formed by mixing $25 \ g$ of heptane and $35 \ g$ of octane is ........ $kPa$. (Molar masses of heptane and octane are $100 \ g \ mol^{-1}$ and $114 \ g \ mol^{-1}$,respectively.)

Which of the following is an ideal solution?

At a particular temperature,the vapour pressures of two liquids $A$ and $B$ are respectively $120 \, mm$ and $180 \, mm$ of mercury. If $2 \, moles$ of $A$ and $3 \, moles$ of $B$ are mixed to form an ideal solution,the vapour pressure of the solution at the same temperature will be (in $mm$ of mercury):