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NEET-XII-Chemistry

exam-1 year:2016

with Solutions - page 2
Qstn# 68 Prvs-QstnNext-Qstn
  • #68
    Equal moles of hydrogen and oxygen gases are
    placed in a container with a pin-hole through which
    both can escape. What fraction of the oxygen
    escapes in the time required for one-half of the
    hydrogen to escape ?
    (1) 1/8
    (2) 1/4
    (3) 3/8
    (4) 1/2
    digAnsr:   1
    Ans : (1)
    Sol. =
    2 2H O
    n n and =
    2 2H O
    t t
    According to Graham's law
    = &implies; =2 2
    2 2
    H O 1 1
    O H 2 2
    r M v / t 32
    r M v / t 2
    = =
    1 / 2
    16 4
    1 / x
    =
    x
    4
    2
    ∴ x = 8
    ∴ Fraction of O2 = 1/8