CBSE Questions for Class 12 Engineering Chemistry Solutions Quiz 2 - MCQExams.com

The vapour pressure (V.P.) of a dilute solution of non-volatile solute is P and the V.P. of pure solvent is $$P^0$$, the lowering of the V.P. is :
  • $$+ve$$
  • $$-ve$$
  • $$P/P^0$$
  • $$P^0/P$$
Which substance does NOT dissolve well in water?
  • $${NH}_{3}$$
  • $${C}_{4}{H}_{10}$$
  • $${C}_{12}{H}_{22}{O}_{11}$$
  • $${H}_{2}{SO}_{4}$$
The van't Hoff factor for a very dilute aqueous solution of $$K\left[Ag\left( CN \right) _{ 2 } \right] $$ is:
  • $$4$$
  • $$3$$
  • $$2$$
  • $$5$$
In case of an electrolyte which dissociates in the solution, the van't hoff factor $$i$$ is :
  • $$>1$$
  • $$<1$$
  • $$1$$
  • $$>1 \ or \  <1$$
Which condition is not satisfied by an ideal solution?
  • $${\Delta}_{mix}H=0$$
  • $${\Delta}_{mix}V=0$$
  • $${\Delta}_{mix}S=0$$
  • Obeyance of Raoult's law
Aqueous solution of glucose was prepared by dissolving $$18g$$ of glucose in $$90g$$ of water. The relative lowering of vapour pressure is equal to 
  • $$1.1$$
  • $$0.0196$$
  • $$20$$
  • $$196$$
Limiting value of Van't Hoff factor of $$[K_4Fe(CN)_6]$$ is $$11$$.
  • True
  • False
Vant Hoff factor for a dilute solution of glucose is:
  • $$0$$
  • $$1$$
  • $$1.5$$
  • $$2$$
Which substance has a higher solubility in cold water and a lower solubility in hot water?
  • $$LiCl$$
  • $$Ca{(OH)}_{2}$$
  • $${CO}_{2}$$
  • $${C}_{6}{H}_{12}{O}_{6}$$
A concentrated solution contains high amount of ________.
  • solvent
  • solute
  • both solute and solvent
  • none of these
100 mL of liquid A and 25 mL of liquid B are mixed to formal solution of volume 125 mL. Then the solution is___________.
  • ideal
  • non-ideal with positive deviation
  • non-ideal with negative deviation
  • cannot be predicted
The main reason for the extremely low solubility of carbon dioxide in benzene $$(C_{6}H_{6})$$ at room temperature is due to which of the following?
  • The increased disorder due to mixing of the solute and solvent.
  • The relatively low strength of the intermolecular forces between carbon dioxide and benzene.
  • The strong hydrogen bonding in benzene.
  • The weak solvation of carbon and oxygen ions by benzene.
Which of the following solution in water will have the lowest vapour pressure?
  • $$0.1 M, NaCI$$
  • $$0.1 M, Sucrose$$
  • $$0.1 M,{ BaCI }_{ 2 }$$
  • $$0.1 M { Na }_{ 3 }{ PO }_{ 4 }$$
Which one of the following salts would have the same value of the van't Hoff factor as that of $$K_3Fe(CN)_6?$$
  • $$Al_2(SO_4)_3$$
  • $$NaCl$$
  • $$Na_2SO_4$$
  • $$Al(NO_3)_3$$
Ideal solution is formed when its components:
  • have zero heat of mixing only
  • have zero volume change on mixing only
  • have zero heat of mixing and zero volume change
  • can be converted into gases
Which of the following components form an ideal solution?
  • Benzene and toluene
  • Acetone and aniline
  • Ethyl alcohol and benzene
  • Water and nitric acid
Identify which of the following statements is FALSE.
  • The vapor pressure of a liquid decreases with increasing atmospheric pressure.
  • The value of an equilibrium constant is dependent on temperature.
  • The rate of a spontaneous reaction cannot be determined solely by its Gibbs free energy.
  • During a phase transition, the temperature of a substance must be constant.
Which of the following would have the lowest vapor pressure in the pure state?
  • Sodium hydroxide because of the strong interparticle forces of ionic solids
  • Methanol because of the hydrogen bonding in the functional group along with the non-polar nature of the carbon hydrogen bonds
  • Water because of the very strong hydrogen bonding in the substances
  • Ammonia because of the unbonded pair of electrons on the central atom coupled with hydrogen bonding in the substance.
Which of the following are true solutions?
  • ENO salt in water
  • Tomato soup
  • Aam panna
  • Filtered black tea
For an ideal solution with $$P^o_A > P^o_B$$ , which of the following is true ?
  • $$^x_{A(I)} = ^ x_{A(v)}$$
  • $$^x_{A(I)} > ^ x_{A(v)}$$
  • $$^x_{A(I)} < ^ x_{A(v)}$$
  • No relationship in their mole fraction
Lowering of vapour pressures of equimolar solution of glucose, sodium chloride and barium nitrate are in the order:
  • Glucose > $$NaCl$$ > $$Ba(NO_{ 3 }) _{ 2 }$$
  • Glucose = $$NaCl$$ = $$Ba(NO_{ 3 }) _{ 2 }$$
  • $$Ba(NO_{ 3 }) _{ 2 }$$ > $$NaCl$$ > Glucose
  • $$NaCl$$ > $$Ba(NO_{ 3 }) _{ 2 }$$ > Glucose
Which one of the following represents the graph between log P on Y-axis and $$\cfrac { 1 }{ T } $$ on X-axis?
When a solution is diluted at constant temperature, its vapour pressure:
  • increases
  • decreases
  • remains same
  • may increase or decrease
The pressure at which liquid and vapour can coexist at equilibrium is called the :
  • limiting vapour pressure
  • real vapour pressure
  • normal vapour pressure
  • saturated vapour pressure
The vapour pressure of water at $$300$$ K in a closed container is $$0.4$$ atm. If the volume of the container is doubled, its vapour pressure at $$300$$ K will be:
  • $$0.8$$ atm
  • $$0.2$$ atm
  • $$0.4$$ atm
  • $$0.6$$ atm
The boiling points of $${ C }_{ 6 }{ H }_{ 6 }, { CH }_{ 3 }{ OH }, { C }_{ 6 }{ H }_{ 5 }{ NH }_{ 2 }$$ and $${ C }_{ 6 }{ H }_{ 5 }{ NO }_{ 2 }$$ are $$80^{ 0 }C, { 65 }^{ 0 }C, { 184 }^{ 0 }C$$ and $$212^{ 0 }C$$ respectively. Which of these will show highest vapour pressure at room temperature?
  • $${ C }_{ 6 }{ H }_{ 6 }$$
  • $${ CH }_{ 3 }OH$$
  • $${ C }_{ 6 }{ H }_{ 5 }{ NH }_{ 2 }$$
  • $${ C }_{ 6 }{ H }_{ 5 }{ NO }_{ 2 }$$
Which characteristics the weak inter molecular forces of attraction in a liquid?
  • High boiling point
  • High vapour pressure
  • High critical temperature
  • High heat of vapourisation
Which of the following solutions will have the maximum lowering of vapour pressure ?
  • 1M - $${ CaCl }_{ 2 }$$
  • 1M-$$NaCl$$
  • 1N - $$Phenol$$
  • 1M - $$Sucrose$$
A solution is obtained by dissolving 12g of urea (Mol.wt.=60) in a litre of solution. Another solution is prepared by dissolving 68.4g of cane sugar(Mol.wt.=342) in a litre of solution at the same temperature. The lowering of vapour pressure in the first solution is:
  • nearly 5 times that of the second solution
  • same as that of second solution
  • double that of second solution
  • nearly one fifth of the second solution
$$12g$$ of urea is present in $$1$$ litre of solution and $$68.4 g$$ of sucrose is separately dissolved in $$1$$ litre of another sample of solution. The lowering of vapour pressure of first solution is :
  • Equal to second
  • Greater than second
  • Less than second
  • Double that of seconds
At a certain temperature, the vapour pressure of water is 90 mm. At the same temperature the vapour pressure of a solution containing a non-volatile solute is 81 mm. The relative lowering of vapour pressure is :
  • $$9$$
  • $$0.9$$
  • $$10$$
  • $$0.1$$
In which of the following pairs of solutions will the values of the Van't Hoff factor be the same?
  • $$0.05$$ M $${ K }_{ 4 }\left[ Fe\left( CN \right) _{ 6 } \right] $$ and $$0.10$$ M $${ FeSO }_{ 4 }$$
  • $$0.20$$ M $$NaCl$$ and $$0.10$$ M $${ BaCl }_{ 2 }$$
  • $$0.05$$ M $${ FeSO }_{ 4 }\left( NH_{ 4 } \right) _{ 2 }{ SO }_{ 4 }.6{ H }_{ 2 }O$$ and $$0.02$$ M $$KCl.{ MgCl }_{ 2 }.{ 6H }_{ 2 }O$$
  • All have same value
The van't hoff factor for a very dilute solution of $${ Fe }_{ 2 }\left( { SO }_{ 4 } \right) _{ 3 }$$ is:
  • $$9$$
  • $$5$$
  • $$24$$
  • $$16$$
Correct combination among the following is 
i) Water can be converted into vapour at $${ 100 }^{ 0 }C$$ only
ii) Vapour pressure can be increased more than the atmospheric pressure at a certain temperature.
iii) Lowering of vapour pressure is directly proportional to mole fraction of solute.
  • All are correct
  • ii only wrong
  • iii only correct
  • All are wrong
In case a solute associates in solution, the van’t Hoff factor is :
  • $$i > 1$$
  • $$i = 1$$
  • $$i < 1$$
  • None of these
For a very dilute aqueous solution of $${ K }_{ 4 }\left[ Fe\left( CN \right) _{ 6 } \right] $$ , van't Hoff factor is :
  • $$i=11$$
  • $$i=5$$
  • $$i=\dfrac { 1 }{ 11 } $$
  • $$i=10$$
For a substance $$A$$ when dissolved in a solvent $$B$$ shows the molecular mass corresponding to $${ A }_{ 3 }$$. The van't Hoff factor will be:
  • $$1$$
  • $$2$$
  • $$3$$
  • $$\dfrac{1}{3}$$
For a non-electrolytic solution, vant Hoff factor is equal to :
  • 0
  • 1
  • between 0 and 1
  • none of the above
The following are some statements about vapour pressure.
I. Vapour pressure of a solution increases with increase in temperature.
II. Liquids with high vapour pressure even at ordinary temperatures are volatile liquids.
III. The temperature at which vapour pressure of solution is equal to atmospheric pressure is called boiling point.
IV. When a non-volatile solute is dissolved in a volatile solvent, its vapour pressure decreases.
Which of the above is/are correct?
  • All are correct
  • II, III and IV
  • I and II
  • II and IV
For a very dilute solution of $${ H }_{ 3 }{ PO }_{ 3 }$$, Van’t Hoff factor is:
  • $$i=7$$
  • $$i=3$$
  • $$i=4$$
  • $$i=5$$
For a given value of the degree of dissociation ($$\alpha$$), which of the following have correct van’t Hoff factor?
  • $$NaCl ; i = 2+ \alpha$$
  • $$Ca ( NO_{3})_{2} ; i =1 + 2\alpha$$
  • $$K_{4}[(Fe(CN)_{6}]  ; i = 1+ 4\alpha$$
  • $$(NH_{4})_{3}PO_{4} ;  i = 3+ \alpha$$
Which of the following is/are true?
  • For the same solution, elevation in boiling point = depression in freezing point
  • Van’t Hoff factor for a dilute solution of $$BaCl_{2}$$ is 3
  • Elevation in boiling point is due to increase in vapour pressure
  • Depression in freezing point is due to decrease in vapour pressure
Which of the following form/s an ideal solution?
  • Ethyl bromide + ethyl iodide
  • Ethyl alcohol + water
  • Chloroform + benzene
  • Benzene + toluene
If a solute under goes dimerization and trimerization, the minimum values of the vant Hoff factors are:
  • 0.50 and 1.50
  • 1.50 and 1.33
  • 0.50 and 0.33
  • 0.25 and 0.67
Highly pure dilute solution of sodium in liquid ammonia:
  • on evaporation yield metals.
  • exhibits electrical conductivity.
  • produces sodium amide and hydrogen gas instantly.
  • acts as powerful reducing agent.
A solution containing components A and B follows Raoults law
  • A - B attraction force is greater than A - A and B - B
  • A - B attraction force is less than A - A and B - B
  • A - B attraction force remains same as A - A and B - B
  • Volume of solution is different from sum of volume of solute and solvent
The Van't Hoff factor will be highest for:
  • Sodium chloride
  • Magnesium chloride
  • Sodium phosphate
  • Urea
Van't Hoff factor for a dilute solution of sodium argento cyanide is :
  • $$2$$
  • $$0.25$$
  • $$0.50$$
  • $$3.0$$
The incorrect statement is :
  • Vapour pressure of a liquid always increases by increasing temperature.
  • Vapour pressure only depends on temperature and not on the nature of substance.
  • Vapour pressure does not depend on the quantity of the liquid taken and the surface area of the liquid.
  • Vapour pressure is not a colligative property & is independent of the concentration of the liquid.
$$0.1  M K_{4} [Fe (CN)_{6}]$$ is 60% ionized. What will be its van't Hoff factor?
  • 1.4
  • 2.4
  • 3.4
  • 4.4
0:0:1


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