R4RIN – MCQs, Mock Tests | IIT JEE IIT JEE Gaseous State

Which of the following is false about gases

1. The molecules possess random movement in all directions
2. Gases intermix freely without the help of external agency
3. They are highly compressible
4. They possess definite volume.

✅ Correct Answer: 4

wo gases X and Y are at same temperature and pressure. The reduced temperature of X is below unity while that of Y is above unity. Thus

1. X can be liquefied by compression but not Y
2. Y can be liquefied by compression but not X
3. both X and Y can be liquefied by compression
4. none of the statement is correct.

✅ Correct Answer: 1

Liquefication of gases cannot be achieved by

1. cooling
2. compressing the gas at all temperatures
3. compressing the gas as well as cooling
4. compressing the gas below critical temperature.

✅ Correct Answer: 2

A pressure of 0.101325 bar when expressed in atmospheres represents

1. 0.01 atm
2. 1 atm
3. 0.1 atm0.1 atm
4. 10 atm.

✅ Correct Answer: 1

Which of the following statement is false?

1. The product PV for fixed amount of gas is independent of temperature.
2. Molecules of different gases have same KE at a given temperature.
3. The gas equation is not valid at high pressure and low temperature.
4. The gas constant per molecule is known as Boltzman constant.

✅ Correct Answer: 1

A rubber balloon permeable to all isotopic forms of hydrogen is filled with heavy hydrogen and placed in tank of pure hydrogen. After some times the balloon will

1. shrink in size
2. expand
3. remain as such
4. shrink to half of its size.

✅ Correct Answer: 2

The value of universal gas constant depends upon

1. temperature of the gas
2. volume of the gas
3. number of moles of gas
4. none of these.

✅ Correct Answer: 4

At constant volume for a foxed number of gas moles the pressure of the gas increases with the rise in temp. because of

1. increase in average molecular speed
2. increased rate of collisions amongst molecules
3. increase in molecular attraction
4. decrease in mean free path.

✅ Correct Answer: 1

An ideal gas is at pressure P and temperature T in a box which has been placed in another evacuated large container. The inner box is pricked so that the gas inside it starts escaping out. What is correct?

1. the temperature falls
2. the temperature rises
3. the temperature remains
4. the sameunpredictable.

✅ Correct Answer: 3

The bottle of liquid ammonia is cooled before opening the seal so as to lower its

1. vapour pressure
2. surface tension
3. viscosity
4. extent of H-bonding.

✅ Correct Answer: 1

The vapour density a diatomic gas with homoatomic molecules is 25. The atomoc mass of a gas will be

1. 150
2. 25
3. 75
4. 22

✅ Correct Answer: 2

Under which of the following conditions the real gases will approach the behaviour of ideal gas?

1. 15 atm 200 K
2. 0.5 atm 500 K
3. 1 atm 273 K
4. 15 atm 500 K.

✅ Correct Answer: 2

For ideal gas isochors refer to the graphs between

1. V and T at constant P
2. P and T at constant V
3. P and V at constant T
4. V/T and T at constant P.

✅ Correct Answer: 2

One litre of gas weighs 2 g at 300 K and 1 atm pressure. If the pressure is made 0.75 atm and temperature is brought down to 250 K the gas will occupy a volume of

1. 2 L
2. 1.11 L
3. 2.22 L
4. 0.7 L.

✅ Correct Answer: 2

The magnitude of van der Waals forces depends upon

1. molecular size
2. number of electrons in the molecule
3. polarisability of molecules
4. all the above factors.

✅ Correct Answer: 4

Which of the following do not pertain to the postulates of kinetic theory of gases?

1. Molecular collisions are perfectly elastic
2. Gas molecules move at random with ever changing speeds
3. Molecular collision against the wall are responsible of gas pressure.
4. KE of a gas is given by the sum of 273 and temperature in celcius scale.

✅ Correct Answer: 4

Real gases deviate from ideal behaviour because the molecules

1. are colourless
2. attract each other
3. contain covalent bonds
4. show Brownian movement.

✅ Correct Answer: 2

Rate of diffusion of a gas is

1. directly proportional to its density
2. directly proportional to its molecular mass
3. directly proportional to the square root of its molecular mass
4. inversely proportional to the square root of its molecular mass.

✅ Correct Answer: 4

For ideal gases isotherm refers to the

1. gases at same temperatures
2. gases at same pressure
3. gases having same heat capacities
4. plot of us V at constant T.

✅ Correct Answer: 4

The temperature of ideal gas can be increased by

1. decreasing the volume and pressure but keeping the amount constant
2. increasing the pressure but keeping the volume and amount constant
3. decreasing the amount but keeping the volume and pressure constant
4. any of b or c operation.

✅ Correct Answer: 4

The state in which 99% matter of the universe exists is

1. Plasma
2. Solid
3. Gaseous
4. Liquid.

✅ Correct Answer: 4

The densities of two gases are in the ratio of 1: 16. The ratio of their rates of diffusion is

1. 16:01
2. 4:01
3. 1:04
4. 1:16

✅ Correct Answer: 2

Which among the following samples of gases contains Avogadro number of atoms at S.T.P.?

1. 2 g of Helium
2. 11.2 L of carbon monoxide
3. 11.2 L of sulphur dioxide
4. 1 mol of phosphine.

✅ Correct Answer: 2

The dimensions of pressure are some as that of

1. Energy
2. Energy per unit volume
3. Force per unit area
4. Force per unit volume.

✅ Correct Answer: 3

When ideal gas undergoes unstrained expansion no cooling occurs because the molecules

1. are above inversion temperature
2. exert no attractive force on each other
3. work equal to loss in kinetic energy
4. collide without loss of energy.

✅ Correct Answer: 2

1000 ml of a gas A at 600 torr and 500 ml of gas B at 800 torr are placed in a 2L flask. The final pressure in atmosphere is

1. 2000
2. 1000
3. 500
4. 0.657.

✅ Correct Answer: 4

The average distance traveled by the molecule between successive collisions is called

1. collision path
2. mean free path
3. collision diameter
4. collision distance.

✅ Correct Answer: 2

If volume of two moles of ideal gas at 540 K is 44.8 L then its pressure will be

1. 1 atm
2. 2 atm
3. 3 atm
4. 4 atm.

✅ Correct Answer: 2

A vessel containing gas at a pressure of 60 cm of Hg was connected to arm A of open end manometer. The atmospheric pressure was recorded as 74 cm of Hg. If mercury in arm A stands at 84.5 cm height the mercury in arm will stand at

1. 70.5 cm
2. 74 cm
3. 24.5 cm
4. 88 cm.

✅ Correct Answer: 1

Hydrogen diffuses 6 times faster than gas X. The molecular mass for X will be

1. 72
2. 140
3. 144
4. 100

✅ Correct Answer: 1

Four soldered ampules of equal volumes contain nitrogen ozone chlorine and helium at ordinary conditions. The largest number of atoms will be found in the ampule containing

1. chlorine
2. ozone
3. helium
4. nitrogen.

✅ Correct Answer: 2

Two flasks of equal capacity contain argon and chlorine gases respectively at room temperature. What is true about them?

1. Both contain same number of atom
2. Cl atoms are half of the Ar atoms
3. Cl atoms are double the number of Ar atoms
4. Chlorine molecules are double the number of argon molecules.

✅ Correct Answer: 3

The behaviour of a real gas approaches ideal behaviour at

1. low temperature low pressure
2. low temperature high pressure
3. vlow temperature high pressure
4. high temperature low pressure.

✅ Correct Answer: 4

1 g of Zn was treated with each of excess of sulphuric acid and excess of NaOH separately. The ratio of the volumes of hydrogen evolved is

1. 1:01
2. 1:02
3. 9:04
4. 2:01

✅ Correct Answer: 1

The temperature at which real gas exhibits ideal behaviour over a wide range of pressure is called

1. Inversion temperature
2. Boyle temperature
3. Reduced temperature
4. Critical temperature.

✅ Correct Answer: 2

Critical temperature of the gas refers to the temperature

1. at which it occupies a volume of 22.4 L
2. at which if gets liquefied at 1 atmosphere
3. below which it always exists as liquid
4. above which it always exists as gas.

✅ Correct Answer: 4

10 g of each of the following gases were taken HF HCl HBr HI under similar conditions then

1. all will have same volume
2. HF will have largest volume
3. HI will have largest volume
4. HBr will have lowest volume.

✅ Correct Answer: 2

Which of the following pairs of gas will diffuse at the same rate under similar conditions?

1. carbon dioxide and nitrous oxide
2. carbon dioxide and nitrogen dioxide
3. carbon dioxide and nitric oxide
4. carbon monoxide and carbon dioxide.

✅ Correct Answer: 4

The value of critical volumes of four gases A B C D are 0.025 L 0.312 L 0.245 L and respectively. The gas with larger value of van der Waal constant b is

1. A
2. D
3. B
4. unpredicatable.

✅ Correct Answer: 4

Same gas is confined to two containers A and B. The pressure volume and temperature (K) of gas in A are three times as compared to that in B. If the mass of gas in A is x g then the mass in B would be

1. x g
2. 0.3x g
3. 0.5x g
4. 3x g.

✅ Correct Answer: 2

Each of the four species hydrogen sulphide (I) protium oxide (II) hydrogen chloride (III) and chlorine (IV) at S.T.P. have been put into four separate vessel each of one litre capacity. The largest number of molecules are present in

1. i
2. ii
3. iii
4. All will have same no. of molecules.

✅ Correct Answer: 3

The vapour density of gas X is 4 times that of Y. If molecular mass of X is

1. M/2
2. 4M
3. M/4
4. 2M.

✅ Correct Answer: 2

The distance between the centres of the molecules at the closest approach is called

1. collision diameter
2. van der Waal distance
3. can der Wall radius
4. covalent radius.

✅ Correct Answer: 1

Three flasks of 2 L capacity were separately filled with argon oxygen and ozone respectively under similar conditions. The ratio of number of atoms in the flasks is

1. 1:01:01
2. 1:02:03
3. 3:02:01
4. 2:02:03

✅ Correct Answer: 2

Which of the following will not change the r.m.s. if the gas molecules?

1. Change in temperature
2. Change in volume at constant T
3. Change in volume at constant T
4. Change in number of gas molecules.

✅ Correct Answer: 2

Which among the following contains Avogadro number of molecules?

1. 36 g of water vapours
2. 49 g of hydrogen sulphate
3. 17 g of ammonia
4. 4.4 g of carbon dioxide.

✅ Correct Answer: 3

Real gases deviate from ideal behaviour because their molecules

1. cause repulsive interactions on one another
2. cause attractive interaction on one anotherare polyatomic
3. do not undergo elastic collisions.
4. None of them

✅ Correct Answer: 2

Three different gases X Y Z of molecular masses 32 64 71 were enclosed in a vessel at constant temperature till equilibrium is reached. Which of the following statement is/are true?

1. Gas X will be at the top of the vessel
2. Gas Y will be at the top of the vessel
3. Gas X will be at the bottom and Z will be at the top
4. Gases will form homogeneous mixture.

✅ Correct Answer: 4

The van der Waal constant b is equal to

1. four times the volume of 1 mol of gas
2. the molecular volume of 1mol of gas
3. four times the actual volume of molecules contained in 1 mol of gas
4. twice the molecular volume of 1 mol of gas.

✅ Correct Answer: 3

Pick up correct answer among the following about Boyles temperature

1. The ratio P/T approaches unity
2. The ratio RT/PV approaches unity
3. The ratio PV/RT approaches unity
4. The ratio PV/RT approaches zero.

✅ Correct Answer: 3

The mixture of three gases X (density 0.09) Y (density 0.178) and Z (density 0.42) is enclosed in a closed vessel at constant temperature. When equilibrium is establisted the

1. gas X will be at the top of the vessel
2. gas Y will be at the top of the vessel
3. gases X Y Z will constitute homogeneous mixture throughout the vessel
4. gas Y will be at the bottom of the vessel.

✅ Correct Answer: 3

500 ml of gas A at 1000 torr and 1000 ml of gas at 800 torr ate placed in an empty container of 2 L capacity. The pressure in the container would be

1. 100 torr
2. 2400 torr
3. 650 torr
4. 1800 mm.

✅ Correct Answer: 3

The rate of diffusion of methane at certain temperature is 2 times that of gas X. The molecular mass of X is

1. 64
2. 32
3. 4
4. 8.0.

✅ Correct Answer: 1

Which of the following is not the postulate of the kinetic theory of gases?

1. gas molecules are in a permanent state of random motion
2. pressure of gas is due to molecular impacts on the walls
3. the molecules are perfectly elastic
4. the molecular collisions are elastic.

✅ Correct Answer: 3

A balloon containing methane is pricked with a sharp needle and quickly plunged into a tank of hydrogen at same pressure. After sometime the balloon will

1. get enlarged
2. get collapsed
3. remain as beforereduce to half of its
4. original size.

✅ Correct Answer: 1

A real gas which obeys van der Waals equation will approach ideal behaviour if

1. a is large b is small
2. a is small b is large
3. a and b both are large
4. a b are negligibly small.

✅ Correct Answer: 4