CBSE Questions for Class 11 Medical Chemistry States Of Matter Gases And Liquids Quiz 7 - MCQExams.com

A Solution of non-volatile solute in water freezes at $$-0.{ 30 }^{ }C.$$ The vapour-pressure of pure water at $$298K$$ is $$23.51mm Hg$$ and $${ K }_{ 1 }$$ for water is $$1.86 K. kg { mol }^{ -1 }$$ Calculate the vapour-pressure of this solution at $$298K.$$
  • $$23.4mm$$
  • $$24.8mm$$
  • $$34.8mm$$
  • $$40mm$$
Calculate the volume occupied by 4 mole of an ideal gas at $$2.5\times { 10 }^{ 5 }{ Nm }^{ -2 }$$ pressure and 300K temperature.
  • $$0.4\ dm^3$$
  • $$0.04\ dm^3$$
  • $$0.3\ dm^3$$
  • None of these
What would be the vapour pressure of 0.5 molal solution of non volatile solute in benzene at $$30^oC$$ ? The vapour pressure of pure benzene at $$30^oC$$ is 119.6 torr.
  • 119.6 torr
  • 121.23 torr
  • 118.52 torr
  • None of these
A mixture of $$He$$ and $$SO_2$$ at one bar pressure contains $$20\%$$ by weight of $$He$$. Partial pressure of $$He$$ be:
  • 0.2 bar
  • 0.4 bar
  • 0.6 bar
  • 0.8 bar
The vapour pressure of pure water is 760 mm at $$25^{ 0 }C$$.The vapour pressure of solution containing 1(m) solution of glucose will be:
  • 761.0 mm
  • 746.5 mm
  • 734.5 atm
  • 746.5 Pa
For  a binary ideal solution, the variation in total vapour pressure versus composition of solution is given by which of the curves?
A balloon weighting $$50 Kg$$ is filled with $$ 685 kg$$ of helium at $$1 atm$$ pressure and $${ 25 }^{ o }C$$. What will be its pay load if it displaced $$5108 kg$$ of air?
  • $$4373 kg$$
  • $$4423 kg$$
  • $$5793 kg$$
  • None of these
Air contains $$79\% \ N_2$$ and $$21\% O_2$$ by volume. If the pressure is $$750 \ mm$$ of $$Hg$$, the partial pressure of oxygen $$(O_2)$$ is:
  • $$157.5\ mmHg$$
  • $$175.5\ mmHg$$
  • $$315.0\ mmHg$$
  • $$257.5\ mmHg$$
In the following graphical representation for reaction $$A \to B$$ there are two types of regions:
1060028_dcf9e61da667498e89596d8678d33981.png
  • $$I$$ and $$II$$ both represent kinetic region at different interval
  • $$I$$ and $$II$$ both represent equilibrium regions at different time interval
  • $$I$$ represents kinetic while $$II$$ represents equilibrium region
  • $$I$$ represents equilibrium while $$II$$ represents kinetic region
$$2.8 g$$ of a gas at $$1atm$$ and $$273K$$ occupies a volume of $$2.24$$ litres. The gas can not be:
  • $${ O }_{ 2 }$$
  • $$CO$$
  • $${ N }_{ 2 }$$
  • $$C_{ 2 }{ H }_{ 4 }$$
The volume of $$3.7 g $$ of a gas at $${ 25 }^{ o }C$$ is the same as the volume of $$0.184 g$$ of $${ H }_{ 2 }$$ at $${ 17 }^{ o }C$$ and same pressure. What is the molecular weight of the gas?
  • $$31.33 g/mol$$
  • $$41.33 g/mol$$
  • $$21.45 g/mol$$
  • $$11.45g/mol$$
$$CuSO_5H_2O_{(s)} \rightleftharpoons {CuSO_4}_{(aq)}$$; $$K_p = 4 \times 10^{-4}\ atm^2$$ 
If the vapor pressure of water is 38 torr then the percentage of relative humidity is:
  • 4
  • 10
  • 40
  • 1
The vapour pressure of water at $$20^{o}C$$ is $$17.54mm Hg$$. Then the vapour pressure of the water in the apparatus is lowered, decreasing the volume of the gas above the liquid to one half of its initial volume (temp. constant) is:
  • $$5.77\ mmHg$$
  • $$16\ mmHg$$
  • $$35.08\ mmHg$$
  • between $$8.77$$ and $$15.54\ mmHg$$
A liquid A and B form an ideal solution. If vapour pressure of pure A and B are $$500N{ m }^{ -2 }$$ and $$200N{ m }^{ -2 }$$ respectively, the vapour pressure of a solution of A and B containing 0.2 mole fraction of A would be:
  • $$700N{ m }^{ -2 }$$
  • $$300N{ m }^{ -2 }$$
  • $$260N{ m }^{ -2 }$$
  • $$140N{ m }^{ -2 }$$
A mixture of ethyl alcohol and propyl alcohol has a vapour pressure of $$290\ mm$$ at $$300\ K$$. The vapour pressure of propyl alcohol is $$200\ mm$$. If the mole fraction of ethyl alcohol is $$0.6$$, its vapour pressure (in $$mm$$) at the same temperature will be:
  • $$300$$
  • $$700$$
  • $$360$$
  • $$350$$
Which of the following is not a matter ?
  • Book 
  • Air 
  • Idea 
  • Cold drink 
For the equilibrium ,$${ 2SO }_{ 3 }(g)\rightleftharpoons 2{ SO }_{ 2 }(g)+{ O }_{ 2 }(g)$$; the partial pressure of $${ SO }_{ 3 }$$, $${ SO }_{ 2 }$$ and $${ O }_{ 2 }$$ gases at $$650 K$$ are respectively $$0.2 bar,0.6 bar$$ and $$0.4 bar$$. If the moles of both oxides of sulphur are so adjusted as equal, what will be the partial pressure of $${ O }_{ 2 }$$?
  • $$4.4$$
  • $$0.44$$
  • $$3.6$$
  • $$1.12$$
Equal weight of methane and hydrogen are mixed in an empty container at $${ 25 }^{ 0 }C$$. The fraction of total pressure exerted by hydrogen is?
  • 1/2
  • 8/9
  • 16/19
  • 1/9
$$3$$ moles of $$P$$ and $$2$$ moles of $$Q$$ are mixed, what will be their total vapour pressure in the solution if their partial vapour pressures are $$80$$ and $$60$$ respectively?
  • $$80$$ torr
  • $$140$$ torr
  • $$720$$ torr
  • $$70$$ torr
A quantity of gas is collected in a graduated tube over the mercury. The volume of gas at $${18}^{o}C$$ is $$50.0mL$$ and the level of mercury in the tube is $$100mm$$ above the outside mercury level The barometer reads $$750$$ torr. Hence, volume at STP is approximately:
  • $$22mL$$
  • $$40mL$$
  • $$20mL$$
  • $$44mL$$
Which of the following expression is true regarding gas laws? 
($$w=$$weight, $$m=$$molar mass)
  • $$\dfrac { { T }_{ 1 } }{ { T }_{ 2 } } =\dfrac { { M }_{ 1 }{ w }_{ 2 } }{ { M }_{ 2 }{ w }_{ 1 } }$$
  • $$\dfrac { { T }_{ 1 } }{ { T }_{ 2 } } =\dfrac { { M }_{ 2 }{ w }_{ 1 } }{ { M }_{ 1 }{ w }_{ 2 } }$$
  • $$\dfrac { { T }_{ 1 } }{ { T }_{ 2 } } =\dfrac { { M }_{ 1 }{ w }_{ 1 } }{ { M }_{ 2 }{ w }_{ 2 } }$$
  • $$\dfrac { { T }_{ 2 } }{ { T }_{ 1 } } =\dfrac { { M }_{ 1 }{ w }_{ 1 } }{ { M }_{ 2 }{ w }_{ 2 } }$$
How many grams of sucrose must be added to $$320g$$ of water to lower the vapour pressure by $$1.5mm$$ $$Hg$$ at $${25}^{o}C$$?
(Given: The vapour pressure of water at $${25}^{o}C$$ is $$23.8mm$$ $$Hg$$ and molar mass of sucrose is $$324.3g/mol$$)
  • $$21.5g$$
  • $$140g$$
  • $$363.36g$$
  • $$160.12g$$
The vapour pressure of a liquid decreases by $$10 torr$$ when a non-volatile solute is dissolved. The mole fraction of the solute in solution is $$0.1$$. What would be the mole fraction of the liquid if the decrease in vapour pressure is $$20torr$$, the same solute being dissolved?
  • $$0.2$$
  • $$0.9$$
  • $$0.8$$
  • $$0.6$$
A gas at a pressure of $$5.0$$ bar is heated from $$0^{o}$$ to $$546^{o}C$$ and is simultaneously compressed to one-third of its original volume. Hence, final pressure is:
  • $$\dfrac {5}{9}$$bar
  • $$15.0$$bar
  • $$30.0$$bar
  • $$45.0$$bar
Which gas does have density $$1,58$$ by air?
  • $$NO_2$$
  • $$N_2O$$
  • $$N_2O_3$$
  • $$NO$$
  • $$CO_2$$
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
Which of the assumptions of the kinetic-molecular theory best explains the observations that a gas can be compressed?
  • Gas molecules move at random with no attractive forces between them
  • The velocity of gas molecules is proportional to their kelvin temperature
  • The amount of space occupied by a gas is much greater than the space occupied by the actual gas molecules
  • In collisions with the walls of the container or with other molecules, energy is conserved
Which of the following statement is not a postulate of kinetic molecular theory of gases?
  • $$K.E.$$ is dependent on temperature
  • $$K.E.$$ is dependent on pressure
  • The molecular collisions are perfectly elastic collisions
  • The pressure of the gas is due to collisions of gas molecules on the walls of the vessel
Which of the following relationships is valid?
  • $$\dfrac {pV}{T}=\dfrac {2}{3}K$$
  • $$\dfrac {pV}{T}=\dfrac {3}{2}K$$
  • $$\dfrac {pV}{T}=2K$$
  • $$\dfrac {pV}{T}=3K$$
The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is $$1:4$$. The ratio of the number of their molecule is _______.
  • $$1:4$$
  • $$7:32$$
  • $$1:8$$
  • $$3:16$$
The mass of glucose that should be dissolved in $$100g$$ water in order to produce same lowering of vapour pressure as produced by dissolving $$1g$$ urea in $$50g$$ of water is?
  • $$1g$$
  • $$2g$$
  • $$6g$$
  • $$12g$$
For which of the following binary solution $${P}_{Total}={P}_{A}^{o}\times {X}_{A}+ {P}_{B}^{o}\times {X}_{B}$$ is followed?
  • Phenol+ Aniline
  • Benzene + Toluene
  • Acetone + Chloroform
  • water + $$HCl$$
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
$$0.157$$ g of a certain gas collected over water occupies a volume of $$135ml$$ at $${ 27 }^{ 0 }C$$ and $$750 mm$$ of Hg. Assuming ideal behaviour , the molecular weight of the gas is: 
(aqueous tension at $${ 27 }^{ 0 }C$$ is $$26.7 mm$$ of $$Hg$$)
  • $$30$$
  • $$32$$
  • $$28$$
  • $$16$$
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
Equal masses of $${ SO }_{ 2, }{ CH }_{ 4 }$$ and $${ CH }_{ 4 }$$ are mixed in empty container at 298 K, when total pressure is 2.1 atm. The partial pressure of $$O_2$$ in the mixture is:
  • $$0.5$$ atm
  • $$0.75$$ atm
  • $$1.2$$ atm
  • $$0.6$$ atm
When a student was given aviscometer, the liquid was sucked with difficulty, the liquid may be:
  • benzene
  • toluene
  • water
  • glycerine
The gas Z in the above fraction is ?
  • Nitrous oxide
  • Nitric Oxide
  • Dinitrogen tetroxide
  • Nitrogen dioxide
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
The density of $$CO_2$$ gas at $$27^0 C$$ and $$1 \,atm$$ pressure is _____ (gram/litre).
  • $$1.78$$
  • $$1.52$$
  • $$1.96$$
  • $$1.20$$
Which of the following curve does not represent Gay-lussac's law?
A vessel has nitrogen gas and water vapours at a total pressure of 1 atm. The partial pressure of water vapour is 0.4 atm. The content of this vessel are transferred completely to another vessel having one-third of the capacity of the original volume at the same temperature, then the total pressure of this system in the new vessel is:
  • 2.5 atm
  • 3 atm
  • 3.4 atm
  • 4.2 atm
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 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 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
The surface tension of the liquid at its boiling point
  • becomes zero
  • becomes infinity
  • is equal to the value at room temperature
  • is half to the value at room temperature
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:
  • $$2 : 2 : 4 : 3$$
  • $$1 : 1 : 1 : 1$$
  • $$1 : 2 : 3 : 4$$
  • $$2 : 2 : 3 : 4$$
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 liquids in each of the following pairs has a higher vapour pressure?
  • Alcohol, glycerine
  • Mercury, water
  • petrol, kerosene
  • None of these
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