“Kinetic Theory of Gases” MCQ with Answer Explanation.

Here below some basic MCQ’s about “kinetic theory of gases” with answer which is explained in details. Let’s check one by which is given below.

1. Which of the following assumptions is NOT part of the kinetic theory of gases?

A) Gas molecules are in constant random motion.
B) The volume of gas molecules is negligible compared to the volume of the container.
C) Gas molecules attract each other significantly.
D) Collisions between gas molecules are perfectly elastic.

Answer: C) Gas molecules attract each other significantly.

Explanation: The kinetic theory assumes that gas molecules do not exert forces on each other except during collisions, so significant attraction is not considered.

2. The process of a gas becoming a liquid is called:

A) Sublimation.
B) Vaporization.
C) Condensation.
D) Freezing.

Answer: C) Condensation.

Explanation: Condensation is the process where a gas transforms into a liquid as it loses energy.

3. The pressure of a gas is directly proportional to its temperature when:

A) Volume is constant.
B) Number of moles is constant.
C) Both volume and number of moles are constant.
D) Both temperature and volume are constant.

Answer: A) Volume is constant.

Explanation: According to Gay-Lussac’s Law, for a fixed amount of gas at constant volume, pressure is directly proportional to temperature.

4. In a gas, the average kinetic energy of the molecules is directly proportional to:

A) Pressure.
B) Volume.
C) Temperature.
D) Molar mass.

Answer: C) Temperature.

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

5. According to the kinetic theory, the temperature of a gas is a measure of:

A) The average potential energy of the molecules.
B) The average kinetic energy of the molecules.
C) The total energy of the molecules.
D) The volume occupied by the gas.

Answer: B) The average kinetic energy of the molecules.

Explanation: Temperature is defined in the context of kinetic theory as a measure of the average kinetic energy of the molecules in a gas.

6. Which gas behaves most ideally under a wide range of temperatures and pressures?

A) Carbon Dioxide (CO2)
B) Nitrogen (N2)
C) Ammonia (NH3)
D) Water vapor (H2O)

Answer: B) Nitrogen (N2)

Explanation: Nitrogen is a diatomic gas that closely follows the ideal gas law under a wide range of conditions, while other gases deviate due to intermolecular forces and molecular size.

7. If the volume of a gas is halved while maintaining the temperature constant, what happens to the pressure?

A) It remains the same.
B) It halves.
C) It doubles.
D) It increases four times.

Answer: C) It doubles.

Explanation: According to Boyle’s Law, pressure is inversely proportional to volume at constant temperature. Thus, halving the volume doubles the pressure.

8. The molecular speed distribution in a gas is described by which distribution?

A) Normal distribution
B) Poisson distribution
C) Maxwell-Boltzmann distribution
D) Exponential distribution

Answer: C) Maxwell-Boltzmann distribution

Explanation: The speed distribution of gas molecules at a given temperature follows the Maxwell-Boltzmann distribution, which describes how speeds are distributed among particles.

9. At absolute zero (0 K), the motion of gas molecules theoretically:

A) Stops completely.
B) Increases.
C) Becomes chaotic.
D) Increases linearly.

Answer: A) Stops completely.

Explanation: Absolute zero is the point at which molecular motion is minimized to its lowest possible energy state, theoretically halting all motion.

10. The principle behind the diffusion of gases is primarily due to:

A) Gravitational forces.
B) The random motion of gas molecules.
C) Intermolecular attractions.
D) The presence of a temperature gradient.

Answer: B) The random motion of gas molecules.

Explanation: Gases diffuse due to the random motion of their molecules, which causes them to spread out and fill the available space.