2. Solved Papers
  3. BHU PMT

BHU PMT BHU PMT (Mains) Solved Paper-2010

  • question_answer
    The vapour pressure of a solvent A is 0.80 atm. When a non-volatile substance B is added to this solvent, its vapour pressure drops to 0.60 atm. The mole fraction of A in the solution is

    A)  0.25                                      

    B)  0.50

    C)  0.75                                      

    D)  0.90

    Correct Answer: C

    Solution :

                     According to Raoulfs law, \[\frac{{{p}^{o}}-{{p}_{s}}}{{{p}^{o}}}={{\chi }_{B}}\] (where,\[{{\chi }_{B}}=\]mole fraction of solute, B) \[\frac{0.80-0.60}{0.80}={{\chi }_{B}}\] \[\frac{0.20}{0.80}={{\chi }_{B}}\] \[\therefore \]  \[{{\chi }_{B}}=0.25\] \[\therefore \]Mole fraction of\[A=1-0.25\] \[=0.75\]


You need to login to perform this action.
You will be redirected in 3 sec spinner