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CBSE Questions for Class 12 Engineering Chemistry Solutions Quiz 7 - MCQExams.com

Two liquids A and B form an ideal solution. The vapour pressure of pure A and pure B are 66mm of Hg and 88mm of Hg, respectively. Calculate the composition of vapour A in the solution which is equilibrium and whose molar volume is 36%.
  • 0.43
  • 0.70
  • 0.30
  • 0.50
Vapour pressure of CCI4 at 24oC is 143mmHg0.05g of the non-volatile solute (mol.wt.=65) is dissolved in 100mlCCI4. Find the vapour pressure of the solution (Density of CCI4=1.58g/cm2)
  • 143.99mm
  • 94.39mm
  • 199.34mm
  • 14.197mm
Which of the liquids in each of the following pairs has a higher vapour pressure?
  • Alcohol, glycerine
  • Mercury, water
  • petrol, kerosene
  • None of these
The vapour pressure of water at 20 is 17.5 mm Hg. If 18 g of glucose { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 } is added to 178.2 g water 20 , the vapour pressure of the resulting solution will be:
  • 17.675 mm Hg
  • 15.750 mm Hg
  • 16.500 mm Hg
  • 17.325 mm Hg
At { 20 }^{ 0 }C, the vapour pressure of diethyl either is 44mm. When 6.4 g. of a non-volatile solute is dissolved in 50g. of either, the vapour pressure falls to 410mm. The Molecular weight of the solute is:
  • 150
  • 130
  • 160
  • 180
The vapour pressure of pure A is 10 torr and at the same temperature when 1\ g of B is dissolved in 20\ gm of A, its vapour pressure is reduced to 9.0 torr. If the molecular mass of A is 200 amu, then the molecular mass of B is:
  • 100\ amu
  • 90\ amu
  • 75\ amu
  • 120\ amu
The vapour pressure of a solvent decreased by 10 mm of mercury when a non-volatile solute was added to the solvent. The mole fraction of the solute in the solution is 0.What should be the mole fraction of the solvent if the decrease in the vapour pressure is to be 20 mm of mercury?
  • 0.4
  • 0.6
  • 0.8
  • 0.2
Vapours of a liquid can exist only at ?
  • below boiling point
  • below critical temperature
  • below inversion temperature
  • above critical temperature
When some NaCl was dissolved in water, the freezing point depression was numerically equal to twice the molal K_f depression constant. The relative lowering of vapour pressure of the solution is nearly:
  • 0.036
  • 0.018
  • 0.0585
  • 0.072
The vapour pressure of pure liquid is 70 Torr at 27^o C. The vapour pressure of a solution of this liquid and another liquid (mole fraction 0.2) is 84 Torr at 27^o C. The vapour pressure of pure liquid B at 27^o C is?
  • 140 Torr
  • 280 Torr
  • 160 Torr
  • 200 Torr
{ \Delta  }_{ f }{ G }^{ o } at 500\ K for substance S in liquid state and gaseous state are +100.7\ kcal\ { mol }^{ -1 } and +103\ kcal\ { mol }^{ -1 } respectively. Vapour pressure of liquid S at 500\ K is approximately equal to: (R= 2\ { cal }\ K^{ -1 }\ { mol }^{ -1 })
  • 0.1\ atm
  • 1\ atm
  • 10\ atm
  • 100\ atm
A solution has a 1:4 mole ratio of pentane to hexane. The vapour pressure of the pure hydrocarbons at 20^{\circ}C are 440 mm of Hg for pentane and 120 mm of Hg for hexane. The mole fraction of pentane in the vapour phase would be?
  • 0.549
  • 0.200
  • 0.786
  • 0.478
Vapour pressure of pure benzene is 119 torr and of toluene is 37.0 torr at the same temperature mole fraction of toluene in vapour phase which is in equilibrium with a solution of benzene and toluene having a mole fraction of toluene 0.50, will be:
  • 0.137
  • 0.205
  • 0.237
  • 0.435
The amount of solute (mol mass=60) that must be added to 180g of water so that the vapour pressure of water is lowered by 10 \% is?
  • 30g
  • 60g
  • 120g
  • 12g
20ml of 1M\ BaCl_2 solution and 25ml of 0.1M Na_2SO_4 are mixed to form BaSO_4. The amount of BaSO_4 precipitated are:
  • 2.5 g
  • 2.5 moles
  • 2.5 millimoles
  • 0.05 millimoles
A mixture of ethanol and propanol has vapor pressure 279 mm of Hg at 300 K. The mol fraction of ethanol in the solution is 0.6 and vapour pressure of pure propanol is 210 mm of Hg. Vapour pressure of pure ethanol will be:
  • 336.6 mm
  • 325 mm
  • 375 mm
  • 415 mm
The vapour pressure of a pure liquid A is 70 torr at 300 K. It forms an ideal solution with another liquid B. The mole fraction of B in the solution is 0.2 and total pressure of solution is 84 torr at 300 K. The vapour pressure of pure liquid B at 27C is ?
  • 0.14 torr
  • 560 torr
  • 140 torr
  • 70 torr
The boiling point of C_{6}H_{6},CH_{3}OH, C_{6}H_{5}NH_{2} and C_{6}H_{5}NO_{2}   are 80^{\circ},\ 65 ^{\circ},\ 184^{\circ} and 212^{\circ} respectively. Which will show highest vapourr pressure at room temperature?
  • C_{6}H_{6}
  • CH_{3}OH
  • C_{6}H_{5}NH_{2}
  • C_{6}H_{5}NO_{2}
For a non-electrolytic solution, van't Hoff factor is equal to:
  • 0
  • 1
  • 2
  • 0\quad <\quad i\quad \le \quad 1
One mole of non volatile solute is dissolved in two moles of water. The vapour pressure of the solution relative to that of water is:
  • \dfrac{2}{3}
  • \dfrac{1}{3}
  • \dfrac{1}{2}
  • \dfrac{3}{1}
If P^o and P^s are the vapour pressure of the solvent and solution respectively. n_ 1 and n_2 are the mole fraction of the solvent and solute respectively, then?
  • P^S=P^o n_1
  • P^S=P^o n_2
  • P^o=P^S n_2
  • P^S=P^o \dfrac { { n }_{ 1 } }{ { n }_{ 2 } }
A mixture of ethyl alcohol and propyl alcohol has vapour pressure of 290mm at 300K. The vapour pressure of propyl alcohol is 200mm. If mole fraction of ethyl alcohol is 0.6 its vapour presssure at same temperature will be:-
  • 360
  • 350
  • 300
  • 700
Vapour pressure diagram of some liquids plotted against temperature are shown below most volatile liquid is 

1131766_5e693d4bb6bb47718b02f7adcd0b89d2.png
  • A
  • B
  • C
  • D
Two liquids, A and B, form an ideal solution. At the specified temperature, the vapour pressure of pure A is 200 mm Hg while that of pure B is 75 mm Hg. If the vapour over the mixture consists of 50 mol percent A, what is the mole percent A in the liquid?
  • 20
  • 76
  • 27
  • 65
The relative decrease in vapour pressure of an aqua solution containing 2 moles of 4NaCl in 3 moles of {H}2_{O} is 0.On reaction with AgNO_3 this solution will form:
  • 1 mol of AgCl
  • 0.25 mol of AgCl
  • 2 mol of AgCl
  • 0.4 mol of AgCl
An ideal solution contains two volatile liquids A\left( p=100\ torr \right) and B\left( p=200\ torr \right) . If mixture contain 1 mole of A and 4 mole of B then total vapour pressure of the distillate is:
  • 150
  • 180
  • 188.88
  • 198.88
The vapour pressure of water is 12.3k \, Pa at 300K. Calculate the vapour pressure 1 molal solution of a non-volatile solute in it.
  • 12.08 \ kPa
  • 1.208 \ Ppa
  • 2.4 \ kPa
  • 0.4 kPa
An ideal solution if obtained by mixing CH_3 CHBr_2 and CH_2Br - CH_2Br in the ratio 2:1
P^o_{CH_3CHBr_2} = 173, P^o_{CH_2BrCH_2Br} = 127. Thus total vapour pressure is:
  • 158
  • 257
  • 137
  • 197
Two liquids A and B have {P}_{A}^{o} and {P}_{B}^{o} in the ratio 1:3 and the ratio of number of moles of A and B in liquid phase are 1:3. Then mole fraction of A in vapour phase in equilibrium with the solution is equal to:
  • 0.1
  • 0.2
  • 0.5
  • 1.0
In an ideal solution of non-volatile solute B in solvent A in 2: 5 molar ratio has vapour pressure 250 mm. If another solution in ratio 3: 4 prepared then vapour pressure above this solution is:
  • 200 mm
  • 250 mm
  • 350 mm
  • 400 mm
Calculate the vapour pressure of a solution at 100^oC containing 3 g of cane sugar in 33 g of water. (Atomic weight of C =12\ u,H=1\ u,O=16\ u)
  • 760 mm Hg
  • 756.9 mm Hg
  • 758.3 mm Hg
  • None of these
A sample of drinking water was found to be severely contaminated with chloroform, {CHCl}_{3}, supposed to be a carcinogen. The level of contamination was 15 ppm (by mass). Express this in percent by mass.
  • 1.5\times {10}^{-3}
  • 4.0\times {10}^{-3}
  • 6\times {10}^{-3}
  • 0.75\times {10}^{-3}
In steam distillation, the vapour pressure of the volatile organic compound is:
  • equal to atmospheric pressure
  • less than atmospheric pressure
  • more than atmosphetic pressure
  • none of the above
A sample of 16g charcoal was brought into contact with   C{  H}_{  4} gas contained in a vessel of 1 litre at  2{ 7 }^{0  }C  . The pressure of gas was found to fall from 760 to 608 torr. The density of charcoal sample is 1.6g/  c{  m}^{ 3 }  . What is the volume of the   C{  H}_{  4} gas adsorbed per gram of the adsorbent at 608 torr and  2{ 7 }^{0  }C  ?
  • 125 mL/g
  • 16.25 mL/g
  • 26 mL/g
  • None of these
The gas Z in the above fraction is ?
  • Nitrous oxide
  • Nitric Oxide
  • Dinitrogen tetroxide
  • Nitrogen dioxide
100\ ml of an aqueous solution contains 6.0\times {10}^{21} solute molecules. The solution is diluted to 1 lit. The number of solute molecules present in 10\ ml of the dilute solution is:
  • 6.0\times {10}^{20}
  • 6.0\times {10}^{19}
  • 6.0\times {10}^{18}
  • 6.0\times {10}^{17}
Lowering in vapour pressure is highest for:
  • 0.2m urea
  • 0.1m glucose
  • 0.1m \, MgSO_4
  • 0.1m \, BaCl_2
Normal boiling point of a liquid is that temperature at which vapour of the liquid pressure of the liquid is equal to:
  • zero
  • 380mm of Hg
  • 760mm of Hg
  • 100mm of Hg
A solution X contains 30 mole percent of A and is in equilibrium with its vapour that contains 40 mole percent of B. The ratio of vapour pressure of pure A and B will be 
  • 2 : 7
  • 7 : 2
  • 3 : 4
  • 4 : 3
Which of the following is an ideal solution
  • Water + ethanol
  • Chloroform + carbon tetrachloride
  • Benzene + toluene
  • Water + hydrochloric acid
The concentration of a salt solution in terms of mass by mass percentage is  20\%  and the mass of the solution is  550 g.  What is the mass of solute present in the solution?
  • 110g
  • 105g
  • 205g
  • 210g
The vapour pressure of a solution containing 5 g of a non electrolyte in 100 g of water at a particular temperature is 2985 N{m}^{-2}. If the vapour pressure of pure water is 3000 N{m}^{-2}, the molecular weight of solute is:
  • 60
  • 120
  • 180
  • 380
The temperature and pressure at which ice, liquid. water and water vapour can exist together are ?
  • { 0 }^{ o }C,\quad 1 atm
  • { 2 }^{ o }C,\quad 4.7atm
  • { 0 }^{ o }C,\quad 4.7mm
  • { -2 }^{ o }C,\quad 4.7mm
All form ideal solution except
  • C_2H_5Br and C_2H_5I
  • C_6H_5Cl and C_6H_5Br
  • C_6H_6 and C_6H_5CH_3
  • C_2H_5I and C_2H_5OH
Vapour pressure is _________ dependent property.
  • Temperature
  • Pressure
  • Volume
  • Density
The solubility of a specific non-volatile salt is  4\mathrm { g }  in 100\mathrm { g }  of water at  25 ^ { \circ } \mathrm { C } .  If  2.0 g,  4.0\mathrm g  and  6.0 g  of the salt added of  100 g  of water at  25 ^ { \circ } \mathrm { C } ,  in system  X , Y  and  Z .  The vapour pressure would be in the order:
  • X < Y < Z
  • X > Y > Z
  • Z > X = Y
  • x > Y = z
At 250^{o}C and 1 atmosphere pressure, the vapour density of PCI_{5} is 57.9 . What will be the dissociation of PCI_{5}-
  • 1.00
  • 0.90
  • 0.80
  • 0.65
A solution X of A and B contains 30 mole \% of A & is in equilibrium with its vapour that contains 40 mole \% of B. The ratio of V.P of pure, A and B will be?
  • 2:7
  • 7:2
  • 3:4
  • 4:3
The vapour pressure of water at 20^0C is 17.54 mm. When 20 g of non-ionic, substance is dissolved in 100 g of water, the vapour pressure is lowered by 0.30 mm.What is the molecular weight of the substances.
  • 210.2
  • 208.16
  • 215.2
  • 200.8
The boiling points of C_6H_6, CH_3OH, C_6H_5 NH_2 and C_6H_5NO_2 are 80^0C, \ 65^0C and 212^0C respectively. Which of the following will have highest vapour pressure at room temperature?
  • C_6H_6
  • CH_3OH
  • C_6H_5NH_2
  • C_6H_5NO_2
0:0:1


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