Order magnitude of osmotic pressure is large

Order magnitude of osmotic pressure is large
99. The molar enthalpy of sublimation of solid benzene is 20.21 K J mol1
. Molar heat of fusion = 10.59 kJ mol1
. Calculate
Kb
for benzene in deg molal1
if boiling point of benzene is 80qC.
(a) 8.446 (b) 6.446 (c) 4.648 (d) 5.468
100. Which among the following is not positive for a non ideal solution showing positive deviation?
(a) ‘H(mixing) (b) ‘V(mixing) (c) ‘G(mixing) (d) ‘S(mixing)
101. 10 g of an ideal non volatile solute of molar mass 100 g mol–1 is dissolved in 100 g of a solvent of molar mass 20. The
elevation of boiling point is ‘T’ K. The molal elevation constant of the solvent is
(a) 20 ‘T (b) 5 ‘T (c) 0.1 ‘T (d) ‘T
102. p0 values of CH3
– OH and C2
H5
– OH at 293 K are 94 mm and 44 mm respectively. Calculate the mole fraction of
each in a mixture assuming ideal behaviour if total vapour pressure is 54 mm.
(a) 0.2, 0.8 (b) 0.25, 0.75 (c) 0.15, 0.85 (d) 0.3, 0.7
Order magnitude of osmotic pressure is large
103. The vapour pressure of a solvent at a certain temperature T is 71.93 mm. It is reduced to 70.5 mm if 10 grams of nonvolatile solute is dissolved in 150 g of the solvent.
Calculate the ratio
molar massof solute
molar massof solvent ,
(a) 2.93 (b) 4.12 (c) 1.92 (d) 3.29
104. 1.068 g of CoCl3
.6H2
O (molar mass = 267g) dissolved in 100 g of water gave a ‘Tf
value = 0.225qC. Kf
for water = 1.86
deg molal1
. Indicate the correct formula for the compound.
105. A 5% solution ( W
V ) of sucrose is isotonic with 1.14% ( W
V ) solution of solute A. Molar mass of A is approximately
equal to
(a) 78 (b) 60 (c) 41 (d) 300
106. The vapour pressure of pure liquids A and B are 300 mm and 650 mm (of Hg) respectively. In a non ideal mixture
of A and B with mole fraction of A as 0.2, the total vapour pressure is 700 mm. Indicate the nature and extent of
the deviation.
(a) positive deviation, 90 mm (b) negative deviation, 80 mm
(c) positive deviation, 120 mm (d) negative deviation, 110 mm
107. In Ostwald–Walker’s experiment, dry air is first passed through a solution of 9.0 g of non volatile solute dissolved in
180 g of water and then through pure water. The loss in weight of the solution was 5.0 g while loss in weight of water
was 0.025 g. Calculate the molar mass of the solute (in g mol1
).