CBSE Questions for Class 11 Engineering Chemistry States Of Matter Quiz 5 - MCQExams.com

At 80C, the vapour pressure of pure benzene is 753 mm Hg and of pure toluene 290 mm Hg. Calculate the composition of a liquid in mole percent which at $$80$$ is in equilibrium with vapour containing 30 mole percent of benzene. 
  • 24, 56
  • 26 ,54
  • 56 24
  • 34 ,76
Which of the following relationships for various gas laws is not correct?
  • $$V_{t} = V_{0} + \dfrac {V_{0}}{273}\times t$$
  • $$\dfrac {V_{1}}{T_{1}} = \dfrac {V_{2}}{T_{1}} (constant\ P)$$
  • $$\dfrac {P_{1}}{T_{1}} = \dfrac {P_{2}}{T_{1}} (constant\ V)$$
  • $$\dfrac {P_{1}T_{1}}{V_{1}} = \dfrac {P_{2}T_{2}}{V_{2}}$$
If $$4\ moles$$ of an ideal gas at $$300\ K$$ occupy volume of $$89.6\ L$$, then pressure of the gas will be :
  • $$2\ atm$$
  • $$1\ atm$$
  • $$1.099\ atm$$
  • $$2.910\ atm$$
Which of the following values does not represent the correct value of $$R$$?
  • $$8.314\ Pa\ m^{2} K^{-1} mol^{-1}$$
  • $$8.314\times 10^{-2} bar\ L\ K^{-1} mol^{-1}$$
  • $$0.0821\ J\ K^{-1} mol^{-1}$$
  • $$8.314\ J\ K^{-1} mol^{-1}$$
How many number of moles of nitrogen will be present in $$2.24\ L$$ of nitrogen gas at $$STP?$$
  • $$9.9$$
  • $$0.099$$
  • $$0.001$$
  • $$1.00$$
The statements for laws of chemical combinations are given below. Mark the statement which is not correct.
  • Matter can neither be created nor destroyed: Law of conservation of mass
  • A compound always contains exactly the same proportion of elements by weight: Law of definite proportions
  • When gases combine they do so in a simple ratio by weight: Gay Lussac's Law
  • Equal volumes of gases at same temperature and pressure contain same number of molecules: Avogadro's Law
What volume in litres will be occupied by $$4.4$$ g of $$CO_2$$ at STP?
  • $$22.4\ L$$
  • $$44.8\ L$$
  • $$12.2\ L$$
  • $$2.24\ L$$
The density of $$O_2$$ is 16 kg/m$$^3$$ at NTP. At what temperature its density will be 19? consider that the pressure remains constant.
  • $$39^oC$$
  • $$43^oC$$
  • $$57^oC$$
  • None of these
$$6 g$$. of the area of dissolved in $$90 g$$. of boiling water. The vapour pressure of the solution is: 
  • $$744.8$$ mm
  • $$758$$ mm
  • $$761$$ mm
  • $$760$$ mm
Which of the following statement about Avogadro's hypothesis is correct?
  • Under similar conditions of temperature and pressure, gases react with each other in simple ratio.
  • Under similar conditions of temperature and pressure, equal volumes of all gases contain same number of molecules
  • At NTP all gases contain same number of molecules
  • Gases always react with gases only at the given temperature and pressure

The volume occupied by $$88\ g$$ of $$CO_2$$ at $$30^{\circ}C$$  and $$1\ bar$$ pressure will be:
  • $$5.05\ L$$
  • $$49.8\ L$$
  • $$2\ L$$
  • $$55\ L$$
To which of the following the Dalton's law of partial pressures is not applicable?
  • $$H_{2}$$ and $$He$$
  • $$NH_{3}$$ and $$HCl$$
  • $$N_{2}$$ and $$H_{2}$$
  • $$N_{2}$$ and $$O_{2}$$
A $$10\ L$$ flask contains a gaseous mixture of $$CO$$ and $$CO_{2}$$ at a total pressure of $$2\ atm$$ and $$298\ K$$. If $$0.20\ mole$$ of $$CO$$ is present, find its partial pressure.
  • $$0.49\ atm$$
  • $$1.51\ atm$$
  • $$1\ atm$$
  • $$2\ atm$$
The correct expression of partial pressure in terms of mole fraction is :
  • $$p_{1} = x_{1}P_{total}, p_{2} = x_{2}P_{total}$$
  • $$p = x_{1}x_{2}P_{total}$$
  • $$P_{total} = p_{1}x_{1}, P_{total} = p_{2}x_{2}$$
  • $$p_{1} + p_{2} = x_{1} + x_{2}$$
The pressure of a $$1 : 4$$ mixture of dihydrogen and dioxygen enclosed in a vessel is one atmosphere. What would be the partial pressure of dioxygen?
  • $$0.8\times 10^{4} atm$$
  • $$0.008\ N\ m^{-2}$$
  • $$8\times 10^{4} N\ m^{-2}$$
  • $$0.25\ atm$$
Dipole-dipole forces act between the molecules possessing permanent dipole. Ends of dipoles possess 'partial charges'. The partial charge is:
  • more than unit electronic charge
  • equal to unit electronic charge
  • less than unit electronic charge
  • double the unit electronic charge
According to kinetic theory of gases, the collisions between molecules of a gas:
  • occur in a zig-zag path
  • occur in a straight line
  • change velocity and energy
  • result in settling down of molecules
Which scientist discovered that the same amount of space was occupied by equal numbers of molecules of gases, irrespective of whether it was hydrogen or chlorine or fluorine?
  • Gay-Lussac
  • Avogadro
  • Marconi
  • Wohler
Which of the following assumptions is incorrect according to kinetic theory of gases?
  • Particles of a gas move in all possible directions in straight lines
  • All the particles, at any particular time, have same speed and same kinetic energy
  • There is no force of attraction between the particles of a gas at ordinary temperature and pressure
  • The actual volume of the gas is negligible in comparison to the empty space between them
Equal masses of helium and oxygen are mixed in a container at $$25^{\circ}C$$. The fraction of the total pressure exerted by oxygen in the mixture of gases is :
  • $$1/3$$
  • $$2/3$$
  • $$1/9$$
  • $$4/9$$
As the temperature increases, average kinetic energy of molecules increases. What would be the effect of increase of temperature on pressure provided the volume is constant?
  • Increases
  • Decreases
  • Remains same
  • Becomes half
'Equal volumes of all gases at the same temperature and pressure contain equal number of molecules'. This law is called as
  • Boyle's law
  • Charle's law
  • Avogadro's law
  • Gay Lussac's law
The kinetic theory of matter helped a great deal in understanding the behaviour of gases. Which of the following statements did not belong to it?
  • When the gas is heated by raising its temperature the molecules move faster
  • The molecules in a gas are always moving
  • Gases are made up of small particles called molecules
  • When molecules collide, they lose energy
Which of the following is correct?
  • Van der waals radius of chlorine is bigger than nitrogen.
  • Covalent radius of nitrogen is bigger than chlorine.
  • Van der waals radius of chlorine is smaller than nitrogen.
  • All are correct.
The kinetic energy of 4 moles of nitrogen gas at 127 is: (R=2 cal $${mol}^{-1}{K}^{-1}$$)
  • 4400 cal
  • 3200 cal
  • 4800 cal
  • 1524 cal
$$3$$ 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 $$60$$ torr respectively?
  • $$80$$ torr
  • $$140$$ torr
  • $$72$$ torr
  • $$70$$ torr
The temperature of $$5$$ mL of a strong acid increases by $$5^o$$C when $$5$$ mL of a strong base is added to it. If $$10$$ mL of each is mixed, temperature should increase by:
  • $$5^o$$C
  • $$10^o$$C
  • $$15^o$$C
  • cannot be known
According to Avogadro's hypothesis, equal volumes of gases under the same conditions of temperature and pressure will contain:
  • the same number of molecules
  • different number of molecules
  • the same number of molecules only if their molecular masses are equal
  • the same number of molecules if their densities are equal.
The $$U-$$tube shown in the figure has a uniform cross section. A liquid is filled up to height $${ h }_{ 1 }$$ and $${ h }_{ 2 }$$ in the two arms and then they are allowed to move, Neglecting viscosity and surface tension, find the state of the liquid when the levels equalize in the two arms. Find the correct statement.
985547_1da97ed0b37a44bfbe66a7c890207bf9.png
  • The liquid will be at rest
  • The liquid will be moving with acceleration
  • The liquid will be moving with velocity

    $$\sqrt { \dfrac { g }{ a({ h }_{ 1 }+{ h }_{ 2 }+h) } }$$
  • The liquid will exert as force to the right on the tube
A balloon filled with $$N_2O$$ is pricked with a sharper point and plunged into a tank of $$SO_2$$ under the same pressure and temperature. The balloon will:
  • enlarged
  • shrink
  • collapse
  • remain unchanged
If the absolute temperature of a gas is doubled and the pressure is reduced to one-half, the volume of the gas will
  • remain unchanged
  • be doubled
  • increase four-fold
  • be reduced to $$1/4th$$
For an ideal gas, a number of moles per liter in terms of its pressure P, gas constant R and temperature T is:
  • PT/R
  • PRT
  • P/RT
  • RT/P
The vapour pressure of a solvent at $$293$$K is $$100$$ mm Hg. Then the vapour pressure of a solution containing $$1$$ mole of a strong electrolyte $$(AB_2)$$ in $$99$$ moles of the solvent at $$293$$ K is:
(Assume complete dissociation of solute)
  • $$103$$ mm Hg
  • $$99$$ mm Hg
  • $$97$$ mm Hg
  • $$101$$ mm Hg
Which of the following has maximum vapour pressure at a given temperature?
If 2 moles of A and 3 moles of B are mixed to form an ideal solution vapour pressure of A and B are 120 and 180 mm of Hg respectively. then the composition of A and B in the Vapour phase when the first traces of vapour are formed in the above case is:
  • $$X^l A = 0.407$$
  • $$X^l A = 0.8$$
  • $$X^l A = 0.109$$
  • $$X^l A = 0.307$$
Two liquids X and Y form an ideal solution. At $$300$$K, vapour pressure of the solution containing $$1$$ mol of X and $$3$$ mol of Y is $$550$$ mm Hg. At the same temperature, if $$1$$ mol of Y is further added to this solution, vapour pressure of the solution increases by $$10$$ mmHg. Vapour pressure (in mm Hg) of X and Y in their pure states will be ________ respectively.
  • $$200$$ and $$300$$
  • $$300$$ and $$400$$
  • $$400$$ and $$600$$
  • $$500$$ and $$600$$
If you are given Avogadro's number of atoms of a gas $$X$$. If half of the atoms are converted into $$X_{(g)}^+$$ by energy $$\Delta H$$. The IE of $$X$$ is :
  • $$\dfrac{2\Delta H}{N_A}$$
  • $$\dfrac{2N_A}{\Delta H}$$
  • $$\dfrac{\Delta H}{2N_A}$$
  • $$\dfrac{N_A}{\Delta H}$$
A solution at $$20^o$$C is composed of $$1.5$$ mol of benzene and $$3.5$$ mol of toluene. If the vapour pressure of pure benzene of pure benzene and pure toluene at this temperature are $$74.7$$ torr and $$22.3$$ torr. respectively, then the total vapour pressure of the solution and the benzene mole fraction in equilibrium with it will be, respectively.
  • $$38.0$$ torr and $$0.589$$
  • $$30.5$$ torr and $$0.389$$
  • $$35.8$$ torr and $$0.280$$
  • $$35.0$$ torr and $$0.480$$
Under the same conditions how many $$ml$$ of $$1\ M$$ $$KOH$$ and $$0.5\ M\ H_2SO_4$$ solutions, respectively, when mixed to form a total volume of $$100\ mL$$ produce the highest rise in temperature?
  • $$67, 33$$
  • $$33, 67$$
  • $$40, 60$$
  • $$50, 50$$
$$2\ L$$ of $$SO_2$$ gas at $$760$$ $$mm\  Hg$$ is transferred to $$10$$ L flask containing oxygen at a participate temperature, the particular pressure of $$SO_2$$ in the flask is:
  • $$63.3 mm\ Hg$$
  • $$152\ mm\ Hg$$
  • $$760\ mm\ Hg$$
  • $$1330\ mm\ Hg$$
An ideal solution has equal mol-fractions of two volatile components A and B in the vapour above the solution, the mol-fractions of A and B.
  • are both $$0.50$$
  • are equal but necessarily $$0.50$$
  • are not very likely to be equal
  • are $$1.00$$ and $$0.00$$ respectively
What is the density of wet air with $$75\%$$ relative humidity at $$1$$ atm and $$300$$ K? 
[Given: vapour pressure of $$H_2O$$ is $$30$$ torr and average molar mass of air is $$29$$g $$mol^{-1}$$]
  • $$1.614$$ g/L
  • $$0.96$$ g/L
  • $$1.06$$ g/L
  • $$1.164$$ g/L
Which of the following statements is/are wrong?
  • At a given temperature the transitional K.E. of one mole of every gas is same which is equal to $$3/2$$ RT
  • K.E. of a gas depends on its mass
  • K.E. depends on the volume
  • K.E. depends on the pressure
Under $$3$$ atm, $$12.5$$ litre of a gas weighs $$15$$ gm. What will be the average speed of gaseous molecules?
  • $$8.028\times 10^4$$ cm/sec
  • $$6.028\times 10^2$$ cm/sec
  • $$8.028\times 10^5$$ cm/sec
  • $$6.028\times 10^4$$ cm/sec
A glass container is sealed with a gas at $$0.800$$ atm pressure and at $$25^o$$C. The glass container sustain pressure of $$2$$ atm. Calculate the temperature to which gas can be heated before bursting the container.
  • $$432^o$$C.
  • $$472^o$$C.
  • $$372^o$$C.
  • $$572^o$$C.
The density of a gas is equal to: 
($$P =$$ pressure, $$V=$$ volume, $$T=$$ temperature, $$R=$$ gas constant, $$n=$$ number of moles and $$M=$$ molecular weight).
  • $$nP$$
  • $$\dfrac{PM_w}{RT}$$
  • $$\dfrac{P}{RT}$$
  • $$\dfrac{M_w}{V}$$
Vapour pressure diagram of some liquids plotted against temperature are shown below most volatile liquid is 

1131766_5e693d4bb6bb47718b02f7adcd0b89d2.png
  • $$A$$
  • $$B$$
  • $$C$$
  • $$D$$
A sample of water gas contains $$42\%$$ by volume of carbon monoxide. If the total pressure is $$760$$ mm of Hg, the partial pressure of carbon monoxide is :
  • $$380$$ mm of Hg
  • $$319.2$$ mm of Hg
  • $$38$$ mm of Hg
  • $$360$$ mm of Hg
A  gaseous mixture containing $$0.35 g $$ of $$N_2$$ and 5600 ml of $$O_2$$ at STP is kept in a 5 litres flask at 300K. The total pressure of the gaseous mixture is :
  • 1.293 atm
  • 1.2315 atm
  • 12.315 atm
  • 0.616 atm
At what relative humidity will $$Na_2SO_4$$ be deliquescent (absorb moisture) when exposed to the air at $$0^o$$C? 
Given: $$Na_2SO_4\cdot 10H_2O(s)\rightleftharpoons Na_2SO_4(s)+10H_2O(g); K_p=4.08\times 10^{-25}$$ and vapour pressure of water $$0^o$$C $$=4.58$$ Torr.
  • Below $$50.5\%$$ but Above $$30.5\%$$
  • Above $$50.5\%$$ 
  • Above $$30.5\%$$
  • Below $$30.5\%$$
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