NEET-XII-Chemistry

exam-1 year:2016

with Solutions - page 2
  • #80
    Which of the following statement about the
    composition of the vapour over an ideal a 1 : 1 molar
    mixture of benzene and toluene is correct? Assume
    that the temperature is constant at 25°C.
    (Given : Vapour Pressure Data at 25°C,
    benzene = 12.8 kPa, Toluene = 3.85 kPa)
    (1) The vapour will contain a higher percentage of
    benzene
    (2) The vapour will contain a higher percentage of
    toluene
    (3) The vapour will contain equal amounts of
    benezene and toluene
    (4) Not enough information is given to make a
    predication
    digAnsr:   1
    Ans : (1)
    Sol. A benzene, B toluene
    1 : 1 molar mixture of A and B
    ∴ =A
    1
    x
    2
    and =B
    1
    x
    2
    = +0 0s A A B BP P X P X
    =  +  =s
    1 1
    P 12.8 3.85 8.325kPa
    2 2

    = = =
    0
    A A
    A
    s
    1
    12.8P X 2Y 0.768
    P 8.325
    ∴ =  =  =B AY 1 Y 1 0.768 0.232
    so, the vapour will contain higher percentage of
    benzene.