Kinetic Theory of Gases NEET MCQ

1. According to the kinetic theory of gases, which of the following statements is correct?

a) Gas molecules are in continuous random motion.
b) Gas molecules attract each other.
c) Gas molecules are relatively large.
d) Gas molecules motion is periodic.

Answer:

a) Gas molecules are in continuous random motion.

Explanation:

The kinetic theory of gases assumes that the gas molecules are in constant, random motion and that they frequently collide with each other and with the walls of their container.

2. The average kinetic energy of gas molecules is directly proportional to:

a) Pressure
b) Volume
c) Temperature
d) Density

Answer:

c) Temperature

Explanation:

The average kinetic energy of the molecules of a gas is directly proportional to the absolute temperature of the gas.

3. At absolute zero, the kinetic energy of gas molecules:

a) Becomes maximum
b) Becomes zero
c) Remains constant
d) Doubles

Answer:

b) Becomes zero

Explanation:

At absolute zero (0 Kelvin), all motion ceases, and the kinetic energy of gas molecules becomes zero.

4. RMS speed of gas molecules is given by:

a) (3kT/m)^1/2
b) (2kT/m)^1/2
c) kT/m
d) 3kT/m

Answer:

a) (3kT/m)^1/2

Explanation:

The root mean square speed (RMS speed) is given by the formula Urms = (3kT/m)^1/2, where k is Boltzmann's constant, T is temperature, and m is the mass of a molecule.

5. The pressure exerted by a gas is due to:

a) The gas volume
b) Collisions of gas molecules with container walls
c) Attraction between gas molecules
d) Size of gas molecules

Answer:

b) Collisions of gas molecules with container walls

Explanation:

The pressure exerted by a gas is due to the continuous collisions of gas molecules with the walls of the container.

6. Which gas will have the highest RMS speed at room temperature?

a) O2
b) H2
c) CO2
d) N2

Answer:

b) H2

Explanation:

RMS speed is inversely proportional to the square root of the molar mass. Hydrogen has the lowest molar mass among the options, so it will have the highest RMS speed.

7. In an ideal gas, the collision between molecules is:

a) Perfectly elastic
b) Perfectly inelastic
c) Partially elastic
d) None of the above

Answer:

a) Perfectly elastic

Explanation:

In an ideal gas, collisions between molecules are perfectly elastic, meaning there's no loss of kinetic energy during collisions.

8. The average translational kinetic energy of a gas molecule at absolute temperature T is given by:

a) kT/2
b) 3kT/2
c) kT
d) 2kT

Answer:

b) 3kT/2

Explanation:

For a monatomic ideal gas, the average translational kinetic energy per molecule is (3/2)kT.

9. If the temperature of a gas doubles and its volume remains constant, the pressure will:

a) Remain the same
b) Halve
c) Double
d) Quadruple

Answer:

c) Double

Explanation:

Using Gay-Lussac's law, if the volume is constant, the pressure of a gas is directly proportional to its temperature. If the temperature doubles, the pressure will also double.

10. For real gases, Van der Waals equation accounts for:

a) Only molecular volumes
b) Only intermolecular attractions
c) Both molecular volumes and intermolecular attractions
d) None of the above

Answer:

c) Both molecular volumes and intermolecular attractions

Explanation:

The Van der Waals equation is an equation of state that extends the ideal gas law to real gases by introducing terms to account for the finite volume of molecules and intermolecular attractions.

11. In the equation PV = nRT, the 'R' represents:

a) Rydberg constant
b) Gas constant
c) Boltzmann constant
d) Radius of atom

Answer:

b) Gas constant

Explanation:

In the ideal gas equation PV = nRT, 'R' stands for the universal gas constant.

12. Which of the following assumptions is NOT made in the kinetic theory of gases?

a) The size of molecules is negligible compared to the distance between them.
b) Collisions of molecules with each other and with the walls of the container are perfectly elastic.
c) The gas consists of large molecules.
d) Gas molecules are in random motion.

Answer:

c) The gas consists of large molecules.

Explanation:

One of the assumptions of the kinetic theory of gases is that the gas molecules are point-sized, or their actual size is negligible compared to the average distance between them.

13. If the RMS speed of the molecules of a gas is v, then the most probable speed is:

a) v/√2
b) v√2
c) 0.82v
d) 1.22v

Answer:

a) v/√2

Explanation:

The most probable speed (or mode speed) is given by vmp = v/√2 where v is the RMS speed.

14. Which of the following laws is NOT based on the kinetic theory of gases?

a) Boyle's law
b) Charles's law
c) Graham's law of diffusion
d) Faraday's law of electrolysis

Answer:

d) Faraday's law of electrolysis

Explanation:

Faraday's law of electrolysis is related to the quantitative aspects of electrolysis and is not based on the kinetic theory of gases.

15. The number of molecules striking a unit area of the wall of a container in one second is called:

a) Pressure
b) Impulse
c) Number density
d) Rate of collision

Answer:

d) Rate of collision

Explanation:

The rate at which molecules strike a unit area of the wall of a container is referred to as the rate of collision.

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