CBSE Questions for Class 11 Engineering Chemistry States Of Matter Quiz 7 - MCQExams.com

Which gas does have density $$1,58$$ by air?
  • $$NO_2$$
  • $$N_2O$$
  • $$N_2O_3$$
  • $$NO$$
  • $$CO_2$$
18 g glucose is added to 178.2 g of water the vapour pressure of water for this aqueous solution at $${ 100 }^{ 0 }C$$ is:
  • 704 torr
  • 759 torr
  • 7.6 torr
  • None of these
In a gaseous mixture at 4 atm pressure, 25% of molecules are Nitrogen, 40% of molecules  are carbon dioxide and the rest are oxygen. The partial pressure of oxygen in the mixture is:
  • 1.40 atm
  • 1.6 atm
  • 1 atm
  • 0.9 atm
The vapour pressure is least for?
  • pure water
  • 0.1m aqueous urea
  • 0.2m aqueous urea
  • 0.3m aqueous urea
Which of the following curve does not represent Gay-lussac's law?
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
One litre of a gas weighs $$2$$g at $$300$$K and $$1$$ atm pressure. If the pressure is made $$0.75$$ atm, at which temperature will one litre of the same gas weighs $$1$$g?
  • $$600$$K
  • $$800$$K
  • $$900$$K
  • $$450$$K
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 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

Which of the given laws of chemical combination is satisfied by the figure?
1841998_f38eefb72b494816afaab449ad11217d.png
  • Law of multiple proportion
  • Gay Lussac's law
  • Avogadro law
  • Law of definite proportion
Vapour pressure of $${ CCI }_{ 4 }$$ at $${ 24 }^{ o }C$$ is $$143 mmHg 0.05$$g of the non-volatile solute (mol.wt.=65) is dissolved in $$100 ml { CCI }_{ 4 }$$. Find the vapour pressure of the solution (Density of $${ CCI }_{ 4 }$$=$$1.58 g/{ cm }^{ 2 }$$)
  • $$143.99 mm$$
  • $$94.39 mm$$
  • $$199.34 mm$$
  • $$14.197 mm$$
The density of a gas is $$2.5$$g/L at $$127^0$$ C and $$1$$ atm. The molecular weight of the gas is:
  • $$82.1$$
  • $$41.05$$
  • $$56$$
  • $$28$$
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
The molecular weight of a gas is $$40$$. At $$400$$K if $$120$$g of this gas has a volume of $$20$$ litres, the pressure of the gas in atm is:
  • $$4.92$$
  • $$5.02$$
  • $$49.6$$
  • $$0.546$$
The vapour pressure of o-nitrophenol at any given temperature is predicted to be: 
  • Higher than that of p-nitrophenol
  • Lower than that of p-nitrophenol
  • Same as that of p-nitrophenol
  • Higher or lower depending upon the size of the vessel
Equal weights of $$HF$$, $$HCl$$ ,$$HBr$$ , and $$HI$$ $${at\ 87}^{0}C$$ and $$750\ mm$$ $$Hg$$ pressure are taken. The correct sequence of these gases in the increasing order of their volume is ?
  •  HI<HBr<HCl<HF
  •  HBr<HI<HCl<HF
  •  HF<HBr<HCl<HI
  •  HI<HBr<HF<HCl
Four one litre flasks are separately filled with gases $$O_2, F_2, CH_4$$ and $$CO_2$$ under same conditions. 

The ratio of the number of molecules in these gases are:
  • $$2 : 2 : 4 : 3$$
  • $$1 : 1 : 1 : 1$$
  • $$1 : 2 : 3 : 4$$
  • $$2 : 2 : 3 : 4$$

A vessel contains equal masses of three gases $$A,\ B,\ C$$ and recorder a pressure of 3.5 bar at $${ 25 }^{ o }$$ C. The molecular mass of $$C$$ is twice that of $$B$$ and molecular mass of $$A$$ is half of B. Find the partial pressure of $$B$$ (in bar the vessel).
  • 3
  • 2
  • 4
  • 1
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
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?
  • $$P^S=P^o n_1$$
  • $$P^S=P^o n_2$$
  • $$P^o=P^S n_2$$
  • $$P^S=P^o \dfrac { { n }_{ 1 } }{ { n }_{ 2 } } $$
Directions: In the following questions, a statement of assertion is followed by a statement of reason. Mark the correct choice as :
Assertion: At equilibrium, vapour phase will be always rich in component which is more volatile. 
Reason: The composition of vapour phase in equilibrium with the solution is determined by the partial pressures of the components.
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true but reason is not the correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false.
$${ \Delta  }_{ f }{ G }^{ o }$$ 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?
  • $$0.549$$
  • $$0.200$$
  • $$0.786$$
  • $$0.478$$
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
$$20$$ litre of an ideal gas, present in a piston fitted cylinder at $$10$$ atm is allowed to expand in a process in which $$P/V$$ is a constant. If final volume of gas is $$60$$  litre, then work done by gas is:
  • $$81.12\ kJ$$
  • $$-81.12\ kJ$$
  • $$40.56\ kJ$$
  • $$-40.56\ kJ$$
A bulb of unknown volume contained an ideal gas at 650mm pressure. A certain amount of the gas was withdrawn and found to occupy 1.5 cc at 700 mm pressure. The pressure of the gas remaining in the bulb was found to be 600 mm. If all measurements are made at the same temperature, the volume of the bulb is ?
  • 21 cc
  • 42 cc
  • 105 cc
  • 63 cc
If the pressure and absolute temperature of $$2\ liters$$ of carbon dioxide are doubled the volume of the gas would  be: 
  • $$2\ litres$$
  • $$4\ litres$$
  • $$5\ litres$$
  • $$7\ litres$$
An open bulb containing air at $$19^{\circ}C$$ was cooled to a certain temperature at which the number of moles of the gaseous molecules increased by $$25\%$$. The final temperature is:
  • $$-39.4^{\circ}C$$
  • $$233.6^{\circ}C$$
  • $$39.4^{\circ}C$$
  • $$240^{\circ}C$$
A vessel contains 0.5 mole each of $${ SO }_{ 2 }{ ,H }_{ 2 }$$ and $$CH_{ 4 }$$. Its outlet was made open and closed after sometime. Thus, order of partial pressure will be:
  • $${ PSO }_{ 2 }>{ PCH }_{ 4 }>{ PH }_{ 2 }$$
  • $${PH}_{2}>{PCH}_{4}>{PSO}_{2}$$
  • $${PH}_{2}>{PSO}_{2}>{PCH}_{4}$$
  • $${PH}_{2} ={PSO}_{2} = {PCH}_{4}$$
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:
  • $$0.137$$
  • $$0.205$$
  • $$0.237$$
  • $$0.435$$
An ideal gas obeying kinetic gas equation :
  • can be liquefied if its temperature is more than critical temperature
  • can be liquefied at any value of any value T and P
  • can not be liquefied under any value of T and P
  • can be liquefied if its pressure is more than critical pressure
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:
  • $$100\ amu$$
  • $$90\ amu$$
  • $$75\ amu$$
  • $$120\ amu$$
A balloon filled with methane $$CH_4$$ is pricked with a sharp point and quickly plunged into a tank of hydrogen at the same pressure. After sometime the balloon will have?
  • Enlarged
  • Collapsed
  • Remained unchanged in size
  • Ethylene $$(C_2H_4)$$ inside it
At a pressure of 760 torr and temperature of 273.15K, the indicated volume of which system is not consistent with the observation?
  • 14 g of $$N_2$$ + 16 g of $$O_2$$; Volume = 22.4 L
  • 4 g of He + 44 g of $$CO_2$$; Volume = 44.8 L
  • 7 g of $$N_2$$ + 36 g of $$O_3$$; Volume = 22.4 L
  • 17 g of $$NH_3$$ + 36.5 g of $$HCl$$, Volume = 44.8 L
The volume of helium gas is 44.8 L at:
  • 100$$^oC$$ and 1 atm
  • 0 $$^o C$$ and 1 atm
  • 0 $$^o \ C$$ and 0.5 atm
  • 100 $$^o \ C$$ and 0.5 atm
How much should the pressure be increased in order to decrease the volume of a gas by $$15\%$$ at a constant temperature?
  • $$15.6\%$$
  • $$17.6\%$$
  • $$6.7\%$$
  • $$8.9\%$$

A gaseous mixture contain 1 gm of $${ H }_{ 2},$$ 4 gm of $$He$$ 7gm of $${ N }_{ 2 } $$ and 8gm of $${ O }_{ 2 }$$. The gas having the highest partial pressure is:
  • $${ H }_{ 2 }$$
  • $${ O }_{ 2 }$$
  • $$He$$
  • $${ N }_{ 2 }$$
An aquatic species need at least 4mg/L of $$O_{2}$$ for their survival. $$O_{2}$$ in water at 273K and 1 atm pressure is $$2.21 \times 10^{-3}$$ mol/L. The partial pressure of $$O_{2}$$ above water(in an atmosphere at 273K) needed for the survival of species is:
  • 0.56 atm
  • 0.056 atm
  • 5.525 atm
  • 5.525 $$\times $$10$$^{-3}$$ atm

In atmosphere which gas have high partial pressure?
  • $${ N }_{ 2 }$$
  • $${ O }_{ 2 }$$
  • $${ H }_{ 2 }O$$
  • $${ CO }_{ 2 }$$
A gaseous mixture containing $$ 0.35_{g} $$ of $$ N_{2} $$ and 5600 ml of $$ O_{2} $$ at STP has kept in a 5 liters at 300K. The total temperature of the gaseous mixture is?
  • 1.293 atm
  • 1.2315 atm
  • 12.315 atm
  • 0.616 atm
0.5 mole of each of $$H, \  SO_2$$ and $$CH_4$$, are kept in a container. A hole was made in the container. After 3 hours, the order of partial pressures in the container will be:
  • $$P(CH_{4}) > P(SO_{2}) > P(H_{2})$$
  • $$P(H_{2}) > P(CH_{4}) > P(SO_{2})$$
  • $$P(SO_{2}) > P(CH_{4}) > P(H_{2})$$
  • $$P(H_{2}) > P(SO_{2}) > P(CH_{4})$$
The molecular weight of $$O_2$$ and $$SO_2$$ are $$32$$ and $$64$$ respectively. If one litre of $$O_2$$ at $$15^0$$C and $$759$$mm pressure contains N molecules, the number of molecules in two litre of $$SO_2$$ under the same conditions of temperature and pressure will be:
  • $$N/2$$
  • $$N$$
  • $$2N$$
  • $$4N$$
Air contains 79% $${ N }_{ 2 }$$ and 21% $${ O }_{ 2 }$$ by volume. If the pressure is $$750$$ of $$Hg$$, the partial pressure of $${ O }_{ 2 }$$ is:
  • $$157.5$$ of $$Hg$$
  • $$175.5$$ of $$Hg$$
  • $$315.0$$ of $$Hg$$
  • $$257.5$$ of $$Hg$$
Vapours of a liquid can exist only at ?
  • below boiling point
  • below critical temperature
  • below inversion temperature
  • above critical temperature
According to Avogadro's law the volume of a gas will ____ as _____ if ____ are held constant.
  • increases, number of moles; P & T
  • decreases, number of moles; P & T
  • increases; T & P; number of moles
  • decreases; P & T; number of moles
Suppose that we change $$U_{RMS}$$ of gas in a closed container from $$5 \times 10^{2}$$ cm/sec to $$10 \times 10^{2}$$ cm/sec, which one of the following might correctly explain how this change was accomplished?
  • By heating the gas w double the temperature
  • By removing 75% of the gas at constant volume we decrease the pressure to one quarter of its original value
  • By heating the gas we quadruple the pressure
  • By pumping in more gas at constant temperature we quadruple the pressure.
For a fixed amount of perfect gas, which of these statements must be true?
  • $$E$$ and $$H$$ each depend only on $$T$$
  • $$C_p$$ is constant
  • $$PdV = nRdT$$ for every infinitesimal process
  • Both $$(A)$$ and $$(C)$$ are true
A weather balloon is inflated with helium. The balloon has a volume of $$100 m^3 $$ and it must be inflated to a pressure of $$ 0.10 atm$$. If $$50 L$$ gas cylinders of helium at a pressure of $$100 atm $$ are used, how many cylinders are needed? Assume that temperature is constant.
  • $$ 2 $$
  • $$ 3 $$
  • $$ 4 $$
  • $$ 1 $$
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 molecular weight of a gas isAt 400K, if 120g of this gas has a volume of 20 litres, the pressure of the gas is?
  • 5.02 atm
  • 0.546 atm
  • 4.92 atm
  • 49.6 atm
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