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NEET-XII-Chemistry

02: Solutions

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  • #2
    Calculate
    the mole fraction of benzene in solution containing 30% by mass in
    carbon tetrachloride.
    Ans : Let
    the total mass of the solution be 100 g and the mass of benzene be 30
    g.
    ∴Mass
    of carbon tetrachloride = (100 - 30)g
    =
    70 g
    Molar
    mass of benzene (C6H6)
    = (6 × 12 + 6 × 1) g mol-1
    = 78
    g mol-1
    ∴Number
    of moles of
    = 0.3846 mol
    Molar
    mass of carbon tetrachloride (CCl4)
    = 1 × 12 + 4 × 355
    =
    154 g mol-1
    ∴Number
    of moles of CCl4
    = 0.4545 mol
    Thus,
    the mole fraction of C6H6 is given as:


    = 0.458