$\bullet$ Dalton's Law of partial pressure states that the total pressure by the mixture of non-reactive gases is equal to the sum of the partial pressures of individual gases.
$\bullet$ ${p_{Total}} = {p_1} + {p_2} + {p_3}$
$\bullet$ Also, ${p_i} = {\chi _i}p$; where pi and $\chi$i are the partial pressure and mole fraction of ith gas respectively and p is the total pressure.
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
A 10.0 L flask contains 64 g of oxygen at 27$^\circ$C. (Assume O2 gas is behaving ideally). The pressure inside the flask in bar is (Given R = 0.0831 L bar K$-$1 mol$-$1)
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
A mixture of N2 and Ar gases in a cylinder contains 7g of N2 and 8g of Ar. If the total pressure of the mixture of the gases in the cylinder is 27 bar, the partial pressure of N2 is : [Use atomic masses (in g mol$ - $1) : N = 14, Ar = 40]
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
A gas at 350 K and 15 bar has molar volume 20 percent smaller than that for an ideal gas under the same
conditions. The correct option about the gas and its compressibility factor (Z) is -
A.
Z < 1 and attractive forces are dominant
B.
Z < 1 and repulsive forces are dominant
C.
Z > 1 and attractive forces are dominant
D.
Z > 1 and repulsive forces are dominant
Correct Answer: A
Explanation:
Compressibility factor (Z ) = ${{{V_{real}}} \over {{V_{ideal}}}}$
Here, Vreal < Videal. Therefore, Z < 1.
In gaseous molecules attractive forces are dominant.
2018
Q11
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
The correction factor ‘a’ to the ideal gas
equation corresponds to
A.
density of the gas molecules
B.
volume of the gas molecules
C.
electric field present between the gas
molecules
D.
forces of attraction between the gas
molecules.
Correct Answer: D
Explanation:
In Ideal gases ‘a’ account for the intermolecular
attractive forces between gas molecules.
2018
Q12
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
Given van der Waals’ constant for NH3
, H2,
O2
and CO2
are respectively 4.17, 0.244, 1.36
and 3.59, which one of the following gases is
most easily liquefied?
A.
NH3
B.
H2
C.
O2
D.
CO2
Correct Answer: A
Explanation:
van der Waals’ constant ‘a’ signifies the
intermolecular forces of attraction between the
particle of gas. So, higher the value of ‘a’, easier
will be the liquefaction of gas.
2016
Q13
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
Equal moles of hydrogen and oxygen gases are placed in a container with a pin-hole through which both can escape. What fraction of the oxygen escapes in the time required for onehalf of the hydrogen to escape?
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
Maximum deviation from ideal gas is expected from
A.
CH4(g)
B.
NH3(g)
C.
H2(g)
D.
N2(g)
Correct Answer: B
Explanation:
The compressibility factor is the term which is
measured for a gas to study its deviation from the
ideal behaviour. Compressibility factor,
$Z = {{PV} \over {nRT}}$
Greater is the difference in the value of Z from
1, greater is the deviation of the gas from ideal
behaviour.
Among the given molecules, NH3 is easily
liquefiable gas which deviates from ideal behaviour
to the maximum extent.
2012
Q17
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
For real gases van der Waals equation is written as
$\left( {p + {{a{n^2}} \over {{V^2}}}} \right)$ (V $-$ nb) = n RT
where $a$ and $b$ are van der Waals constants. Two sets of gases are
(I) O2, CO2, H2 and He
(II) CH4. O2 and H2
The gases given in set-I in increasing order of b and gases given in set-II in decreasing order of $a$, are arranged below. Select the correct order from the following
A.
(I) He < H2 < CO2 < O2 (II) CH4 > H2 > O2
B.
(I) O2 < He < H2 < CO2 (II) H2 > O2 > CH4
C.
(I) H2 < He < O2 < CO2 (II) CH4 > O2 > H2
D.
(I) H2 < O2 < He < CO2 (II) O2 > CH4 > H2
Correct Answer: C
Explanation:
Van der Waal gas constant '$a$' represent intermolecular force of attraction of gaseous molecules and Van der Waal gas constant 'b' represent effective size of molecules . Therefore order should be
(I) H2 < He < O2 < CO2 (II) CH4 > O2 > H2
2012
Q18
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
A certain gas takes three times as long to effuse out as helium. Its molecular mass will be
A.
27 u
B.
36 u
C.
64 u
D.
9 u
Correct Answer: B
Explanation:
According to Graham's law of diffusion
$r \propto {1 \over {\sqrt d }} \propto {1 \over {\sqrt M }}$
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
50 mL of each gas A and of gas B takes 150 and 200 seconds respectively for effusing through a pin hole under the similar conditions. If molecular mass of gas B is 36, the molecular mass of gass A will be
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
A bubble of air is underwater at temperature 15oC and the pressure 1.5 bar. If the bubble rises to the surface where the temperature is 25oC and the pressure is 1.0 bar, what will happen to the volume of the bubble?
$ \therefore $ Volume of bubble will be almost
1.6 time to initial volume of bubble.
2011
Q22
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
In Duma's method of estimation of nitrogen 0.35 g of an organic compound gave 55 mLof nitrogen collected at 300 K temperature and 715 mm pressure. The percentage composition of nitrogen in the compound would be (aqueous tension at 300 K = 15 mm).
$ \therefore $ 46.098 mL of nitrogen = ${{1 \times 46.098} \over {22400}}$ mol
Weight of nitrogen = ${{1 \times 46.098} \over {22400}}$ $ \times $ 28 = 0.057 g
Percent composition of nitrogen in 0.35 g of
compound
= ${{0.0576} \over {0.35}} \times 100$ = 16.45 %
2011
Q23
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
Two gases A and B having the same volume diffuse through a porous partition in 20 and 10 seconds respectively. The molecular mass of A is 49 u. Molecular mass of B will be
A.
50.00 u
B.
12.25 u
C.
6.50 u
D.
25.00 u
Correct Answer: B
Explanation:
We know that ${{{r_A}} \over {{r_B}}} = {{v/{t_A}} \over {v/{t_B}}} = \sqrt {{{{M_B}} \over {{M_A}}}} $
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
A gaseous mixture was prepared by taking equal mole of CO and N2. If the total pressure of the mixture was found 1 atmosphere, the partial pressure of the nitrogen (N2) in the mixture is
A.
0.5 atm
B.
0.8 atm
C.
0.9 atm
D.
1 atm
Correct Answer: A
Explanation:
Number of moles $ \Rightarrow $ nCO = nN2
Volume of container is same. So, VCO = VN2
.
Also,
temperature is same for both the gases thus,
TCO = TN2
According to ideal gas equation,
PV = nRT
Now, V, n, R and T for both gases are same. So,
PCO = PN2
Now, total pressure is 1 atm and according to
Dalton’s law of partial pressure,
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
The energy absorbed by each molecule (A2) of a substance is 4.4 $ \times $ 10$-$19 J and bond energy per molecule is 4.0 $ \times $ 10$-$19 J. The kinetic energy of the molecule per atom will be
A.
2.2 $ \times $ 10$-$19 J
B.
2.0 $ \times $ 10$-$19 J
C.
4.0 $ \times $ 10$-$20 J
D.
2.0 $ \times $ 10$-$20 J
Correct Answer: D
Explanation:
Energy absorbed by each molecule = Bond
energy per molecule + Kinetic energy per molecule
$ \Rightarrow $ 4.4 × 10–19 J = 4.0 × 10–19 J + Kinetic energy per
molecule
$ \Rightarrow $ 0.4 × 10–19 = Kinetic energy per molecule
Kinetic energy per atom =
Kinetic energy per molecule
2
=
0.4 × 10–19
2
= 0.2 × 10–19 J
= 2 × 10–20 J
2008
Q28
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
Volume occupied by one molecule of water (density = 1 g cm$-$3) is
A.
3.0 $ \times $ 10$-$23 cm3
B.
5.5 $ \times $ 10$-$23 cm3
C.
9.0 $ \times $ 10$-$23 cm3
D.
6.023 $ \times $ 10$-$23 cm3
Correct Answer: A
Explanation:
1 mole of water contains 6.023 × 1023 molecules
of water
6.023 × 1023 molecules of water weigh = 18 g
So, 1 molecule of water weighs = ${{18} \over {6.023 \times {{10}^{23}}}}$
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
If a gas expands at constant temperature, it indicates that
A.
kinetic energy of molecules remains the same
B.
number of the molecules of gas increases
C.
kinetic energy of molecules decreases
D.
pressure of the gas increases.
Correct Answer: A
Explanation:
Kinetic energy of a gas is expressed as
K.E = ${3 \over 2}nRT$
Thus, on expansion of fixed amount of gas at
constant temperature the kinetic energy remains
constant.
2003
Q30
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
In Haber process 30 litres of dihydrogen and 30 litres of dinitrogen were taken for reaction which yielded only 50% of the expected product. What will be the composition of gaseous mixture underthe aforesaid condition in the end ?
Balanced chemical equation for Haber's process
is as follows :
3H2 + N2 $ \to $ 2NH3
It is given that only 50% of the expected product
is formed hence only 10 litre of NH3 is formed.
Therefore, composition of gaseous mixture at the
end is as follows :
N2 used = 5 litres
N2 left = 30 L – 5 L = 25 L
H2 used = 15 litres,
H2 legt = 30 L – 15 L = 15 L
NH3 = 10 L
2002
Q31
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
Van der Waal's real gas, acts as an ideal gas, at which conditions?
A.
High temperature, low pressure
B.
Low temperature, high pressure
C.
High temperature, high pressure
D.
Low temperature, low pressure
Correct Answer: A
Explanation:
At higher temperature and low pressure
real gas acts as an ideal gas.
2001
Q32
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
The beans are cooked earlier in pressure cooker because
A.
boiling point increases with increasing pressure
B.
boiling point decreases with increasing pressure
C.
extra pressure of pressure cooker softens the beans
D.
internal energy is not lost while coocking in pressure cooker.
Correct Answer: B
Explanation:
When water pressure increases in the pressure
cooker, water boils at lower temperature and the
beans in pressure cooker are cooked earlier.
2000
Q33
NEET
MCQ
iCON Education HYD, 79930 92826, 73309 7282610 Mar 2026
Which of the following expressions correctly
represents the relationship between the average
molar kinetic energy, KE, of CO and N2 molecules
at the same temperature ?
A.
KECO = KEN2
B.
KECO > KEN2
C.
KECO < KEN2
D.
cannot be predicted unless volumes of the
gases are given
Correct Answer: A
Explanation:
Average molar kinetic energy = ${3 \over 2}nRT$
As temperature is same hence average kinetic
energy of CO and N2 will be same.