In a mixture of liquids A and B, if the mole fractions of component A in vapour phase and liquid mixture are $x_1$ and $x_2$ respectively, then the total vapour pressure of liquid mixture is (where $\mathrm{P}_{\mathrm{A}}^{\circ}$ and $\mathrm{P}_{\mathrm{B}}^{\circ}$ are the vapour pressures of pure A and B )

• A

  $\frac{\mathrm{P}_{\mathrm{B}}^{\circ} x_1}{x_2}$
• B

  $\frac{\mathrm{P}_{\mathrm{B}}^{\circ} x_2}{x_1}$
• Correct answer
  C

  $\frac{\mathrm{P}_{\mathrm{A}}^{\circ} x_2}{x_1}$
• D

  $\frac{\mathrm{P}_{\mathrm{A}}^{\circ} x_1}{x_2}$

Hence, the correct answer is option: 'C'.