CBSE Questions for Class 11 Engineering Chemistry States Of Matter Quiz 4 - MCQExams.com

Mole fraction of the component A in vapour phase is $$x_1$$ and mole fraction of component A in liquid mixture is $$x_2$$, then ($$p^0_A =$$ vapour pressure of pure A; $$p^0_B =$$ vapour pressure of pure B), the total vapour pressure of liquid mixture is :
  • $$p^0_A\dfrac{x_2}{x_1}$$
  • $$p^0_A\dfrac{x_1}{x_2}$$
  • $$p^0_B\dfrac{x_1}{x_2}$$
  • $$p^0_B\dfrac{x_2}{x_1}$$
What is the vapour pressure of a solution of glucose which has an osmotic pressure of 3 atmospheres at $$20^C?$$ The vapour pressure of water at $$20^oC$$ is $$17.39 mm$$. Consider the density of solution equal to that of the solvent.
  • $$12.35 mm$$
  • $$14.35 mm$$
  • $$16.35 mm$$
  • $$17.35 mm$$
Which of the following are correct for an ideal gas?
  • $${ \left( \cfrac { \partial U }{ \partial V } \right) }_{ T }=0\quad $$
  • $${ \left( \cfrac { \partial H }{ \partial P } \right) }_{ T }=0$$
  • $${ \left( \cfrac { \partial T }{ \partial P } \right) }_{ H }=0\quad $$
  • $${ \left( \cfrac { \partial P }{ \partial T } \right) }_{ H }=0\quad $$
At $$25^oC$$, the vapour pressure of pure benzene is 100 torr, while that of pure ethyl alcohol is 44 torr. Assuming ideal behaviour, calculate the vapour pressure at $$25^oC$$ of a solution which contains 10 g of each substance.
  • 33.775 torr
  • 54.775 torr
  • 64.775 torr
  • 60.775 torr
5 gram each of the following gases at $$87^{\circ}C$$ and $$750\ mm$$ pressure is taken. Which of them will have the least volume?
  • $$HF$$
  • $$HCl$$
  • $$HBr$$
  • $$HI$$
For 1 mole  of a real gas. graph between P and V  is given as at $${27^ \circ }$$C
1299491_de53827c719d47d68a9d336d88e08a90.PNG
  • 2 atm
  • 3 atm
  • 30 atm
  • 20 atm
Which of the following do not pertain to the postulates of kinetic theory of gases?
  • The gas molecules are perfectly elastic
  • Speed of gas molecules are every changing
  • Pressure exerted by the gas is due to the collision of molecules with the walls of the container
  • Kinetic energy of a gas is given by the sum of $$273$$ and temperature in Celsius scale
Plot of Maxwell's distribution of velocities is given below:
which of following is correct?
654454_eb65a8304fc646848f5db3cffddaa3ec.png
  • $$T_{1} > T_{2}$$
  • $$T_{1} < T_{2}$$
  • $$v_{1} < v_{2}$$
  • $$f_{1} > f_{2}$$
Which of the following property indicates weak intermolecular forces of attraction in liquid?
  • High heat of vaporization
  • High vapour pressure
  • High critical temperature
  • High boiling point
At $$27^{\circ}C$$ a sample of ammonia gas exerts a pressure of $$5.3\ atm$$. What is the pressure when the volume of the gas is reduced to one-tenth of the original value at the same temperature?
  • $$0.53\ atm$$
  • $$5.3\ atm$$
  • $$53\ atm$$
  • None of these
Soap bubbles can be formed floating in air by blowing soap solution in air, with the help of a glass tube, but not water bubbles. It is because
  • The excess pressure inside water bubble being more due to large surface tension
  • The excess pressure inside water bubble being less due to large surface tension
  • The excess pressure inside water bubble being more due to large viscosity
  • The excess pressure inside water bubble being less due to less viscosity
The following graphs illustrate: 
667491_7f8051aff01e4c1ea89d2564e5a42584.png
  • Dalton's law
  • Boyle's law
  • Charles' law
  • Gay-Lussac's law
The temperature, at which the density of $$O_{2}$$ at $$1\ atm$$, is the same as that of $$CH_{4}$$ at S.T.P is:
  • $$273^{\circ}C$$
  • $$100^{\circ}C$$
  • $$546^{\circ}C$$
  • $$150^{\circ}C$$
Equal weights of two gases of molecular weight $$4$$ and $$40$$ are mixed. The pressure of the mixture is $$1.1$$ atm. The partial pressure of the light gas in this mixture is :
  • $$0.55$$ atm
  • $$0.15$$ atm
  • $$1$$ atm
  • $$0.11$$ atm
Assume that you take a flask, evacuate it to remove all the air and find it's mass to be 478.1 g .You then fill the flask with argon to a pressure of 2.15 atm and reweigh it. What would the balance read (in grams) of the flask has a volume of 7.35 L and the temperature is $$ 20^0 C$$ ?
  • 203.6 g
  • 504.3 g
  • 471.1 g
  • None of these
A balloon contains $$14.0\ L$$ of air at $$760\ torr.$$. What will be the volume of the balloon when it is taken to a depth of $$10\ ft$$ in a swimming pool? Assume that the temperature of the air and water are equal (density: $$Hg=13.6\ g/mL$$)
  • $$11.0$$
  • $$11.3$$
  • $$10$$
  • $$10.8$$
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 $$0.2$$. What should be the mole fraction of the solvent, if the decrease in the vapour pressure is to be $$20\ mm$$ of mercury?
  • $$0.8$$
  • $$0.6$$
  • $$0.4$$
  • $$0.2$$
At a constant temperature, which of the following aqueous solutions will have the maximum vapour pressure?

[Mol weight: $$NaCl=58.5,{ H }_{ 2 }{ SO }_{ 4 }=98.0g.{ mol }^{ -1 }$$]
  • $$1$$ molal $$NaCl$$
  • $$1$$ molar $$NaCl$$
  • $$1$$ molal $${H}_{2}{SO}_{4}$$
  • $$1$$ molar $${H}_{2}{SO}_{4}$$
A spherical soap bubble of radius $$1\ cm$$ is formed inside another of radius $$3\ cm$$. The radius of single soap bubble which maintains the same pressure differences as inside the smaller and outside the larger soap bubble is ________ $$cm$$.
  • $$1$$
  • $$0.75$$
  • $$0.5$$
  • $$0.25$$
'a' moles of $$PCl_5$$, undergoes, the thermal dissociation as: $$PCl_5\rightleftharpoons PCl_3+Cl_2$$, the mole fraction of $$PCl_3$$ at equilibrium is $$0.25$$ and the total pressure is $$2.0$$ atmosphere. The partial pressure of $$Cl_2$$ at equilibrium is?
  • $$2.5$$
  • $$1.0$$
  • $$0.5$$
  • None
On the surface of the earth at $$1\ atm$$ pressure, a balloon filled with $$H_{2}$$ gas occupies $$500\ mL$$. This volume is $$5/6$$ of its maximum capacity. The balloon is left in air. It starts rising. The height above which the balloon will burst if temperature of the atmosphere remains constant and the pressure decreases $$1\ mm$$ for every $$100\ cm$$ rise of height is:
  • $$120\ m$$
  • $$136.67\ m$$
  • $$126\ m$$
  • $$100\ m$$
The two bulbs of volume $$5$$ litre and $$10$$ litre containing an ideal gas at $$9\ atm$$ and $$6\ atm$$ respectively are connected. What is the final pressure in the two bulbs if the temperature remains constant ? 
  • $$12\ atm$$
  • $$21\ atm$$
  • $$15\ atm$$
  • $$7\ atm$$
The P-T graph as given below was observed for a process of an ideal gas, which of the following statement is true?
758805_3fbc26840e104ae09b1fb90e6da5940f.png
  • $$w = +ve, \triangle H = +ve$$
  • $$w = -ve, \triangle H = -ve$$
  • $$w = -ve, \triangle H = +ve$$
  • $$w = +ve, \triangle H = -ve$$
What will be the pressure of the gaseous mixture when $$0.5\ L$$ of $$H_{2}$$ at $$0.8$$ bar and $$2.0\ L$$ of dioxygen at $$0.7$$ bar are introduced in a $$1\ L$$ vessel at $$27^{\circ}C$$?
  • $$2.5 \ bar$$
  • $$2.1 \ bar$$
  • $$1.8 \ bar$$
  • None of these
The $$K_p$$ for $$2SO_{2(g)+O_{2(g)}}\rightleftharpoons 2SO_{3(g)}$$ is $$5.0\,atm^{-1}$$.What is the equilibrium partial pressure of $$O_2$$ if the equilibrium pressure of $$SO_2$$ and $$SO_3$$ are equal?
  • 0.2
  • 0.3
  • 0.4
  • 0.1
An ideal gas undergoes a process in which $$T = T_{0} + aV^{3}$$, where $$T_{0}$$ and $$'a'$$ are positive constants and $$V$$ is molar volume. The molar volume for which pressure will be minimum is :
  • $$\left (\dfrac {T_{0}}{2a}\right )^{1/3}$$
  • $$\left (\dfrac {T_{0}}{3a}\right )^{1/3}$$
  • $$\left (\dfrac {a}{2T_{0}}\right )^{1/3}$$
  • None of these
If the mean free-path of gaseous molecule if 60 cm at a pressure of $$1\times 10^{-4}mm$$ mercury what will be its mean free-path when the pressure is increased to $$ 1\times 10^{-2}$$ mm mercury.
  • $$ .0 \times 10^{-1} cm$$
  • 0.6 cm
  • $$ .0 \times 10^{-2} cm$$
  • $$ .0 \times 10^{3} cm$$
Assuming the volume is held constant, what happens to the pressure of gas when the absolute temperature doubles?
  • It is doubled
  • It is quadrupled
  • It is halved
  • None of these
Which of the following mixtures of gases does not obey Dalton's law of partial pressure?
  • $$O_{2}$$ and $$CO_{2}$$
  • $$N_{2}$$ and $$O_{2}$$
  • $$Cl_{2}$$ and $$O_{2}$$
  • $$NH_{3}$$ and $$HCl$$
The given diagram shows percentage composition of gases $$P, Q, R$$ and other gases present in air.
Which of the following statements is/ are correct regarding gases $$P, Q$$ and $$R$$?
(i) $$P$$ can be fixed in soil by certain bacteria present in roots of leguminous plants.
(ii) $$P$$ supports combustion whereas $$Q$$ and $$R$$ help in extinguishing fire.
(iii) Plants and animals release $$R$$ in respiration whereas plants use $$Q$$ in photosynthesis.
(iv) $$R$$ entraps sun's heat and makes earth warm and hospitable.
811494_4daa3bf34c9c48ccaa741604de5fbb65.jpg
  • (i) and (iv) only
  • (ii) and (iii) only
  • (i), (ii) and (iv) only
  • (iii) only
Which mixture of gases at room temp does not obey daltons law of partial pressure?
  • $$He + Ne + O_{2}$$
  • $$CO_{2} + N_{2} + O_{2}$$
  • $$NH_{3} + HCl + O_{2}$$
  • $$N_{2} + O_{2} + CH_{4}$$
A open ended mercury manometer is used to measure the pressure exerted by a trapped gas as shown in the figure. Initially manometer shows no difference in mercury level in both columns as shown in figure.
After sparking $$A$$ dissociates according to following reaction 
$$A(g)\longrightarrow B(g)+3C(g)$$
If pressure of Gas $$A$$ decreases to $$0.9atm$$. Then
(Assume temperature to be constant and is $$300K$$)
781062_7be9bc1616374a2a98da1093a8638463.PNG
  • total pressure increased to $$1.3$$ atm
  • total pressure increased by $$0.3$$ atm
  • total pressure increased by $$22.3cm$$ of $$Hg$$
  • difference in mercury level is $$228mm$$
If the pressure of gas contained in a closed vessel is increased by 0.4% when heated by 1 degree C its initial temperature must be _____
  • $$20K$$
  • $$250K$$
  • $$25^oC$$
  • $$300K$$
Which one of the following gases is lighter than air?
  • Carbon dioxide
  • Chlorine
  • Oxygen
  • Hydrogen
The property utilized in the manufacture of lead shots is
  • Specific weight of liquid lead
  • Specific gravity of liquid lead
  • Compressibility of liquid lead
  • Surface tension of liquid lead
The molecular weights of $$O_2$$ and $$N_2$$ are $$32$$ and $$28$$ respectively. At $$15^0$$C, the pressure of $$1$$gm $$O_2$$ will be the same as that of $$1$$ gm $$N_2$$ in the same bottle at the temperature:
  • $$-21^0$$C
  • $$-13^0$$C
  • $$15^0$$C
  • $$56.4^0$$V
The molecular weight of $$O_2$$ and $$N_2$$ are 32 and 28 respectively. At $$15^0C$$, the pressure of 1 gm $$O_2$$ will be the same as that of 1 gm $$N_2$$ in the same bottle at the temperature ?
  • $$-21^0C$$
  • $$-13^0C$$
  • $$15^0C$$
  • $$56.4^0V$$
Lowering of vapour pressure in $$2$$ molal aqueous solution at $$373K$$ is____________.
  • $$0.35$$ bar
  • $$0.022$$ bar
  • $$0.22$$ bar
  • $$0.035$$ bar
The rms speed of hydrogen is $$\sqrt { 7 }$$ times the rms speed of nitrogen. If T is the temperature of the gas, then:
  • $${ T }_{ { H }_{ 2 } }={ T }_{ { N }_{ 2 } }$$
  • $${ T }_{ { H }_{ 2 } }>{ T }_{ { N }_{ 2 } }$$
  • $${ T }_{ { H }_{ 2 } }<{ T }_{ { N }_{ 2 } }$$
  • $${ T }_{ { H }_{ 2 } }={ \sqrt { 7 } T }_{ { N }_{ 2 } }$$
For the reaction
$$A(g)+B(g)\rightleftharpoons C(g)$$, the equilibrium partial pressures are $${P}_{A}=0.15atm$$, $${P}_{B}=0.10atm$$ and $${P}_{C}=0.30atm$$. The value of the pressure was so reduced that after attainment of equilibrium again, the partial pressures of $$A$$ and $$B$$ were doubled. The partial pressure of $$C$$ would be:
  • $$0.30atm$$
  • $$0.60atm$$
  • $$1.20atm$$
  • $$1.80atm$$
On a humid day in summer, the mole fraction of gaseous $$H_{2}O$$ (water vapour) in the air at $$25^0$$C can be as high as $$0.0287$$. Assuming a total pressure of $$0.977$$ atm. What is the partial pressure of dry air?
  • $$94.9$$ atm
  • $$0.949$$ atm
  • $$949$$ atm
  • $$0.648$$ atm
The ratio of the vapour pressure of a solution to the vapour pressure of the solvent is:
  • equal to the mole fraction of the solvent
  • equal to the mole fraction of the solute
  • directly proportional to mole fraction of the solute
  • None of the above
At a given temperature, total vapour pressure in Torr of a mixture volatile components A and B is given by 
$$P_{Total}=120-75X_B$$
Hence, vapour pressure of pure A and B respectively (in Torr) are ?
  • 120, 75
  • 120, 195
  • 120, 45
  • 75, 45
Two flasks of equal volume have been joined by a narrow tube of negligible volume. Initially, both flasks are at 300K containing 0.6 mole of $$O_2$$ at 0.5 atm pressure. one of the flasks is placed in the thermostat of 600K. FInd the number of mole of $$O_2$$ gas in each flask.
  • 0.5mol and 0.3 mol
  • 0.5mol and 0.2 mol
  • 0.4mol and 0.2 mol
  • 0.6mol and 0.3 mol
Among the following substances, the lowest vapour pressure is exerted by:
  • water
  • alcohol
  • ether
  • mercury
Water and chlorobenzene are immiscible liquids. Their mixture boils at $$89^o$$C under a reduced pressure of $$7.7 \times 10^4$$ Pa. The vapour pressure of pure water at $$89^o$$C is $$7 \times 10^4$$ Pa. Weight percent of chlorobenzene in the distillate is:
  • 50
  • 60
  • 79
  • 38.46
At $$80^0$$C, the vapour pressure of pure liquid A is $$250$$mm of Hg and that of pure liquid B is $$1000$$ mm of Hg. If a solution of A and B boils at $$80^0$$C and $$1$$ atm pressure, the amount of A in the mixture is :$$(1atm = 760mm$$Hg)
  • $$50$$ mole percent
  • $$52$$ mole percent
  • $$32$$ mole percent
  • $$48$$ mole percent
At $$80^o$$C, the vapour pressure of pure liquid $$A$$ is $$250$$ mm of $$Hg$$ and that of pure liquid $$B$$ is $$1000$$ mm of $$Hg$$. If a solution of $$A$$ and $$B$$ boils at $$80^o$$ and $$1$$ atm pressure, the amount of $$A$$ in the mixture is? 
($$1$$ atm $$=760$$ mm Hg).
  • $$50$$ mole percent
  • $$52$$ mole percent
  • $$32$$ mole percent
  • $$48$$ mole percent
If the concentration of water vapour in the air is $$1\%$$ and the total atmospheric pressure equals $$1$$atm then the partial pressure of water vapour is?
  • $$0.1$$ atm
  • $$1$$ mm Hg
  • $$7.6$$ mm Hg
  • $$100$$ atm
Two moles of pure liquid 'A' ($$P^o_A$$ = 80mm of Hg) and 3 moles of pure liquid 'B' ($$P^o_B$$ = $$120$$mm of $$Hg$$) are mixed. Assuming ideal behaviour.
  • Vapour pressure of the mixture is $$104$$ mm of $$Hg$$
  • Mole fraction of liquid '$$A'$$ in Vapour pressure is $$0.3077$$
  • Mole fraction of '$$B$$' in vapour pressure is $$0.692$$
  • Mole fraction of '$$B$$' in vapour pressure is $$0.785$$
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