Question 1: Palette 1/37

JEE Mains 2025 MCQ

At the sea level, the dry air mass percentage composition is given as nitrogen gas: 70.0 , oxygen gas: 27.0 and argon gas: 3.0 . If total pressure is 1.15 atm , then calculate the ratio of following respectively:

(i) partial pressure of nitrogen gas to partial pressure of oxygen gas

(ii) partial pressure of oxygen gas to partial pressure of argon gas

(Given: Molar mass of N, O and Ar are 14, 16 and $40 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively.)

A

$5.46,17.8$

B

$2.96,11.2$

C

$4.26,19.3$

D

$2.59,11.85$

Question 2: Palette 2/37

JEE Mains 2023 MCQ

Arrange the following gases in increasing order of van der Waals constant 'a'

A. Ar

B. $\mathrm{CH}_{4}$

C. $\mathrm{H}_{2} \mathrm{O}$

D. $\mathrm{C}_{6} \mathrm{H}_{6}$

Choose the correct option from the following.

A

D, C, B and A

B

A, B, C and D

C

B, C, D and A

D

C, D, B and A

Question 3: Palette 3/37

JEE Mains 2023 MCQ

For 1 mol of gas, the plot of pV vs. p is shown below. p is the pressure and V is the volume of the gas

What is the value of compressibility factor at point A ?

A

$1+\frac{b}{V}$

B

$1-\frac{a}{RTV}$

C

$1+\frac{a}{RTV}$

D

$1-\frac{b}{V}$

Question 4: Palette 4/37

JEE Mains 2022 MCQ

Which amongst the given plots is the correct plot for pressure (p) vs density (d) for an ideal gas?

A

B

C

D

Question 5: Palette 5/37

JEE Mains 2022 MCQ

An evacuated glass vessel weighs 40.0 g when empty, 135.0 g when filled with a liquid of density 0.95 g mL^$-$1 and 40.5 g when filled with an ideal gas at 0.82 atm at 250 K. The molar mass of the gas in g mol^$-$1 is :

(Given : R = 0.082 L atm K^$-$1 mol^$-$1)

A

35

B

50

C

75

D

125

Question 6: Palette 6/37

JEE Mains 2021 MCQ

Which one of the following is the correct PV vs P plot at constant temperature for an ideal gas? (P and V stand for pressure and volume of the gas respectively)

A

B

C

D

Question 7: Palette 7/37

JEE Mains 2021 MCQ

The unit of the van der Waals gas equation parameter 'a' in $\left( {P + {{a{n^2}} \over {{V^2}}}} \right)(V - nb) = nRT$ is :

A

kg m s^$-$2

B

dm³ mol^$-$1

C

kg m s^$-$1

D

atm dm⁶ mol^$-$2

Question 8: Palette 8/37

JEE Mains 2021 MCQ

The interaction energy of London forces between two particles is proportional to r^x, where r is the distance between the particles. The value of x is :

A

3

B

$-$3

C

$-$6

D

6

Question 9: Palette 9/37

JEE Mains 2020 MCQ

A mixture of one mole each of H₂ , He and O₂ each are enclosed in a cylinder of volume V at temperature T. If the partial pressure of H₂ is 2 atm, the total pressure of the gases in the cylinder is :

A

14 atm

B

38 atm

C

6 atm

D

22 atm

Question 10: Palette 10/37

JEE Mains 2020 MCQ

Which one of the following graphs is not correct for ideal gas?


d = Density, P = Pressure, T = Temperature

A

II

B

III

C

I

D

IV

Question 11: Palette 11/37

JEE Mains 2020 MCQ

Identify the correct labels of A,B and C in the following graph from the options given below :


Root mean square speed (V_rms); most probable speed (V_mp); Average speed (V_av)

A

A - V_av ; B - V_rms ; C - V_mp

B

A - V_rms ; B - V_mp ; C - V_av

C

A - V_mp; B- V_av; C - V_rms

D

A - V_mp ; B - V_rms ; C - V_av

Question 12: Palette 12/37

JEE Mains 2019 MCQ

Points I, II and III in the following plot respectively correspond to
(V_mp : most probable velocity)

A

V_mp of O₂ (400 K); V_mp of N₂ (300 K); V_mp of H₂ (300 K)

B

V_mp of N₂ (300 K); V_mp of H₂ (300 K); V_mp of O₂ (400 K)

C

V_mp of H₂ (300 K); V_mp of N₂ (300 K); V_mp of O₂ (400 K)

D

V_mp of N₂ (300 K); V_mp of O₂ (400 K); V_mp of H₂ (300 K)

Question 13: Palette 13/37

JEE Mains 2019 MCQ

Consider the following table :

Gas	a/(k Pa dm6 mol-1)	b/(dm3 mol-1)
A	642.32	0.05196
B	155.21	0.04136
C	431.91	0.05196
D	155.21	0.4382

a and b are vander Waals constants. The correct statement about the gases is :

A

Gas C will occupy more volume than gas A; gas B will be more compressible than gas D

B

Gas C will occupy lesser volume than gas A; gas B will be more compressible than gas D

C

Gas C will occupy lesser volume than gas A; gas B will be lesser compressible than gas D

D

Gas C will occupy more volume than gas A; gas B will be lesser compressible than gas D

Question 14: Palette 14/37

JEE Mains 2019 MCQ

At a given temperature T, gases Ne, Ar, Xe and Kr are found to deviate from ideal gas behaviour. Their equation of state is given as

$p = {{RT} \over {V - b}}$ at T.

Here, b is the van der Waals constant. Which gas will exhibit steepest increase in the plot of Z (compression factor) vs p?

A

Xe

B

Ne

C

Ar

D

Kr

Question 15: Palette 15/37

JEE Mains 2019 MCQ

Consider the van der Waals constants, a and b, for the following gases.

Gas	Ar	Ne	Kr	Xe
a/ (atm dm6 mol–2)	1.3	0.2	5.1	4.1
b/ (10–2 dm3 mol–1)	3.2	1.7	1.0	5.0

Which gas is expected to have the highest critical temperature?

A

Ne

B

Kr

C

Xe

D

Ar

Question 16: Palette 16/37

JEE Mains 2019 MCQ

An open vessel at 27^oC is heated until two fifth of the air (assumed as an ideal gas) it has escaped from the vessel assuming that the volume of the vessel remains constant, the temperature at which the vessel has been heated is -

A

750 K

B

500^oC

C

750^oC

D

500 K

Question 17: Palette 17/37

JEE Mains 2019 MCQ

The volume of gas A is twice than that of gas B. The compressibility factor of gas A is thrice than that of gas B at same temperature. The pressures of the gases for equal number of moles are -

A

2P_A = 3P_B

B

3P_A = 2P_B

C

P_A = 3P_B

D

P_A = 2P_B

Question 18: Palette 18/37

JEE Mains 2019 MCQ

0.5 moles of gas A and x moles of gas B exert a pressure of 200 Pa in a container of volume 10 m³ at 1000 K. Given R is the gas constant in JK^$-$1mol^$-$1, x is :

A

${{2R} \over {4 + R}}$

B

${{2R} \over {4 - R}}$

C

${{4 + R} \over {2R}}$

D

${{4 - R} \over {2R}}$

Question 19: Palette 19/37

JEE Mains 2018 MCQ

Assuming ideal gas behaviour, the ratio of density of ammonia to that of hydrogen chloride at same temperature and pressure is : (Atomic wt. of Cl = 35.5 u)

A

1.46

B

0.46

C

1.64

D

0.64

Question 20: Palette 20/37

JEE Mains 2017 MCQ

At 300 K, the density of a certain gaseous molecule at 2 bar is double to that of dinitrogen (N₂ ) at 4 bar. The molar mass of gaseous molecule is :

A

28 g mol^$-$1

B

56 g mol^$-$1

C

112 g mol^$-$1

D

224 g mol^$-$1

Question 21: Palette 21/37

JEE Mains 2017 MCQ

Among the following, the incorrect statement is :

A

At low pressure, real gases show ideal behaviour.

B

At very low temperature, real gases show ideal behaviour.

C

At very large volume, real gases show ideal behaviour.

D

At Boyle’s temperature, real gases show ideal behaviour.

Question 22: Palette 22/37

JEE Mains 2016 MCQ

Initially, the root mean square (rms) velocity of N₂ molecules at certain temperature is $u$. If this temperature is doubled and all the nitrogen molecules dissociate into nitrogen atoms, then the new rms velocity will be :

A

u/2

B

2u

C

4u

D

14u

Question 23: Palette 23/37

JEE Mains 2016 MCQ

At very high pressures, the compressibility factor of one mole of a gas is given by :

A

${{pb} \over {RT}}$

B

1 + ${{pb} \over {RT}}$

C

1 $-$ ${{pb} \over {RT}}$

D

1 $-$ ${b \over {\left( {VRT} \right)}}$

Question 24: Palette 24/37

JEE Mains 2016 MCQ

Two closed bulbs of equal volume $(V)$ containing an ideal gas initially at pressure ${p_i}$ and temperature ${T_1}$ are connected through a narrow tube of negligible volume as shown in the figure below. The temperature of one of the bulbs is then raised to ${T_2}.$ The final pressure ${p_f}$ is :

A

$2{p_i}\left( {{{{T_2}} \over {{T_1} + {T_2}}}} \right)$

B

$2{p_i}\left( {{{{T_1}{T_2}} \over {{T_1} + {T_2}}}} \right)$

C

${p_i}\left( {{{{T_1}{T_2}} \over {{T_1} + {T_2}}}} \right)$

D

$2{p_i}\left( {{{{T_1}} \over {{T_1} + {T_2}}}} \right)$

Question 25: Palette 25/37

JEE Mains 2014 MCQ

If Z is a compressibility factor, van der Waals equation at low pressure can be written as:

A

Z = 1 + $RT \over Pb$

B

Z = 1 - $a \over VRT$

C

Z = 1 - $Pb \over RT$

D

Z = 1 + $Pb \over RT$

Question 26: Palette 26/37

JEE Mains 2013 MCQ

For gaseous state, if most probable speed is denoted by C*, average speed by $\mathop C\limits^{\_\_} $ and mean square speed by C, then for a large number of molecules the ratios of these speeds are:

A

C*: $\mathop C\limits^{\_\_} $ : C = 1.128 : 1.225 : 1

B

C*: $\mathop C\limits^{\_\_} $ : C = 1.225 : 1.128 : 1

C

C*: $\mathop C\limits^{\_\_} $ : C = 1 : 1.225 : 1.128

D

C*: $\mathop C\limits^{\_\_} $ : C = 1 : 1.128 : 1.225

Question 27: Palette 27/37

JEE Mains 2012 MCQ

The compressibility factor for a real gas at high pressure is :

A

1 + RT/pb

B

1

C

1 + pb/RT

D

1–pb/RT

Question 28: Palette 28/37

JEE Mains 2011 MCQ

'a’ and `b’ are van der Waals’ constants for gases. Chlorine is more easily liquefied than ethane because

A

a and b for Cl₂ < a and b for C₂H₆

B

a and b for Cl₂ > a and b for C₂H₆

C

a for Cl₂ > a for C₂H₆ and b Cl₂ < b for C₂H₆

D

a for Cl₂ < a for C₂H₆ and b Cl₂ > b for C₂H₆

Question 29: Palette 29/37

JEE Mains 2010 MCQ

If 10^–4 dm³ of water is introduced into a 1.0 dm³ flask to 300 K, how many moles of water are in the vapour phase when equilibrium is established ?
(Given : Vapour pressure of H₂O at 300 K is 3170 Pa ; R = 8.314 J K^–1 mol^–1)

A

5.56 x 10^–3 mol

B

1.53 x 10^–2 mol

C

4.46 x 10^–2 mol

D

1.27 x 10^–3 mol

Question 30: Palette 30/37

JEE Mains 2007 MCQ

Equal masses of methane and oxygen are mixed in an empty container at 25^oC. The fraction of the total pressure exerted by oxygen is

A

2/3

B

1/2

C

1/3 $\times$ 273/298

D

1/3

Question 31: Palette 31/37

JEE Mains 2005 MCQ

Which one of the following statements is NOT true about the effect of an increase in temperature on the distribution of molecular speeds in a gas?

A

The most probable speed increases

B

The fraction of the molecules with the most probable speed increases

C

The distribution becomes broader

D

The area under the distribution curve remains the same as under the lower temperature

Question 32: Palette 32/37

JEE Mains 2004 MCQ

In Van der Waals equation of state of the gas law, the constant ‘b’ is a measure of

A

intermolecular repulsions

B

intermolecular collisions per unit volume

C

Volume occupied by the molecules

D

intermolecular attraction

Question 33: Palette 33/37

JEE Mains 2004 MCQ

As the temperature is raised from 20°C to 40°C, the average kinetic energy of neon atoms changes by a factor of which of the following?

A

1/2

B

2

C

$313\over293$

D

$\sqrt{313\over293}$

Question 34: Palette 34/37

JEE Mains 2003 MCQ

According to the kinetic theory of gases, in an ideal gas, between two successive collisions of a gas molecule travels

A

in a wavy path

B

in a straight line path

C

with an accelerated velocity

D

in a circular path

Question 35: Palette 35/37

JEE Mains 2002 MCQ

Value of gas constant R is

A

0.082 litre atm

B

0.987 cal mol^-1 K^-1

C

8.3 J mol^-1 K^-1

D

83 erg mol^-1 K^-1

Question 36: Palette 36/37

JEE Mains 2002 MCQ

For an ideal gas, number of moles per litre in terms of its pressure P, gas constant R and temperature T is

A

PT/R

B

PRT

C

P/RT

D

RT/P

Question 37: Palette 37/37

JEE Mains 2002 MCQ

Kinetic theory of gases proves

A

only Boyle's law

B

only Charle's law

C

only Avogadro's law

D

All of these