The vapour pressure of pure liquid is 70 Torr at $27^{\large\circ}C$.The vapour pressure of a solution of this liquid and another liquid (mole fraction 0.2) is 84 Torr at $27^{\large\circ}C$.The vapour pressure of pure liquid B at $27^{\large\circ}C$ is

Question

$\begin{array}{1 1}\text{140 Torr}\\\text{280 Torr}\\\text{160 Torr}\\\text{200 Torr}\end{array} $