A mixture of two miscible volatile ideal liquids P and Q (obeying Raoult's law) is kept in a vessel (molar ratio of P and Q in the mixture is $m$ ). At a suitable temperature $T$, the vapour above the liquid is condensed in another vessel. The liquid obtained on condensation is allowed to evaporate and establish equilibrium with its vapour. The vapour is then condensed in another vessel. The process of such evaporation and condensation is repeated for $n$ times. If the ratio of the vapour pressure of pure $P$ to that of pure $Q$ is $p$, the molar ratio of P and Q in the condensed liquid obtained after $n^{\text {th }}$ cycle (for finite $n \gt 1$ ) is

• Correct answer
  A

  $p^n m$
• B

  $p m^n$
• C

  $p^{n / 2} m^{n / 2}$
• D

  $p^n m^n$

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