NEET 2025 MCQ with Answer Explanation : “Ideal Gas Equation”.

Here below some basic MCQ’s about “Ideal Gas Equation” with Answer which is explained in details. Let’s check one by one which is given below.

1. Which of the following laws relates the volume of a gas to the number of moles at constant temperature and pressure?
   A) Boyle’s Law
   B) Charles’s Law
   C) Avogadro’s Law
   D) Dalton’s Law

Answer: C) Avogadro’s Law

Explanation: Avogadro’s Law states that the volume of a gas is directly proportional to the number of moles when temperature and pressure are held constant.

2. What does the constant 𝑅
   R in the Ideal Gas Equation represent?
   A) The gas density
   B) The molar volume of a gas
   C) The ideal gas constant
   D) The molar mass

Answer: C) The ideal gas constant

Explanation: R is a constant that relates the energy scale in physics to the temperature scale in thermodynamics.

3. Under which conditions do real gases behave most like ideal gases?
   A) Low temperature and high pressure
   B) High temperature and low pressure
   C) High pressure and low temperature
   D) Low pressure and high temperature

Answer: B) High temperature and low pressure

Explanation: Real gases behave more ideally under conditions of high temperature and low pressure, where intermolecular forces and particle volume become negligible.

4. Which of the following is a limitation of the Ideal Gas Equation?
   A) It cannot predict the behavior of real gases at high temperatures.
   B) It does not account for intermolecular forces.
   C) It is only valid for monatomic gases.
   D) It applies only in vacuum conditions.

Answer: B) It does not account for intermolecular forces.

Explanation: The Ideal Gas Equation assumes no intermolecular forces, which is a significant limitation when dealing with real gases.

5. If the volume of an ideal gas is doubled at constant temperature, what happens to the pressure?
   A) It doubles
   B) It remains constant
   C) It halves
   D) It quadruples

Answer: C) It halves

Explanation: According to Boyle’s Law, at constant temperature, pressure is inversely proportional to volume. If volume increases, pressure decreases.

6. What happens to the pressure of an ideal gas if the temperature is increased while keeping volume constant?
   A) Pressure decreases
   B) Pressure remains constant
   C) Pressure increases
   D) Pressure fluctuates

Answer: C) Pressure increases

Explanation: According to Gay-Lussac’s Law, pressure increases with temperature if volume is held constant.

7. What is the relationship between the number of moles and the volume of an ideal gas at constant temperature and pressure?
   A) Directly proportional
   B) Inversely proportional
   C) Exponential
   D) No relationship

Answer: A) Directly proportional

Explanation: According to Avogadro’s Law, the volume of an ideal gas is directly proportional to the number of moles at constant temperature and pressure.

8. Which variable is held constant in the process described by Charles’s Law?
   A) Pressure
   B) Volume
   C) Number of moles
   D) Temperature

Answer: A) Pressure

Explanation: Charles’s Law states that at constant pressure, the volume of a gas is directly proportional to its temperature.

9. The Ideal Gas Equation can be rearranged to calculate which of the following?
   A) Molar mass of a gas
   B) Average kinetic energy of gas molecules
   C) Rate of diffusion
   D) Density of a gas

Answer: D) Density of a gas

10. At what temperature (in Kelvin) does the behavior of a gas become more ideal?
    A) 0 K
    B) 100 K
    C) 273 K
    D) High temperature

Answer: D) High temperature

Explanation: Gases behave more ideally at higher temperatures due to increased kinetic energy, which reduces the effect of intermolecular forces.