Question bank/JEE Advanced/Chemistry

Liquids $\mathbf{A}$ and $\mathbf{B}$ form ideal solution for all compositions of $\mathbf{A}$ and $\mathbf{B}$ at $25^{\circ} \mathrm{C}$. Two such solutions with 0.25 and 0.50 mole fractions of $\mathbf{A}$ have the total vapor pressures of 0.3 and 0.4 bar, respectively. What is the vapor pressure of pure liquid $\mathbf{B}$ in bar?

Source: JEEBench (IIT Delhi) / JEE Adv 2020 Paper 2