NEET Chemistry Gaseous State MCQs Set D

DPMT

 

1. The temperature at which real gases obey the ideal gas laws over a wide range of pressures is called: 

(1) Critical temperature
(2) Inversion temperature

(3) Boyle temperature
(4) Reduced temperature

 

2. When two ice cubes are pressed over each other, they unite to form one cube. Which of the following forces is responsible to hold them together? 

(1) Dipole forces
(2) van der Waal forces

(3) Covalent forces
(4) Hydrogen bond forces

 

3. At high pressure Vanderwall equation becomes

 

8. By what factor does the average velocity of a gaseous molecule increase when the absolute temperature is doubled? 

(1) 1.4
(2) 2.0
(3) 2.8
(4) 4.0

 

9. What will happen to the volume of a bubble of air found underwater in a lake, where the temperature is 15°C and the pressure is 1.5 atm, if the bubble then rises to the surface where the temperature is 25°C and the pressure is 1.0 atm?

(1) Its volume will become greater by a factor of 2.5

(2) Its volume will become greater by a factor of 1.6.

(3) Its volume will become greater by a factor of 1.1

(4) Its volume will become smaller by a factor of 0.70

 

10. Which noble gas is most abundant in atmosphere? 

(1) He
(2) Ne
(3) Ar
(4) Kr

 

ANSWERS

Question. Which of the following statements are true regarding the kinetic theory of gases?
a. The pressure of the gas is directly proportional to the average speed of the molecules
b. The root mean square speed of the molecules is directly proportional to the pressure
c. The rate of diffusion is directly proportional to average speed of the molecules
d. The average kinetic energy per molecule is directly proportional to the absolute temperature
Answer : C, D

Question. A partition divided a container having insulated walls into two compartment I and II. The same gas fills the two compartments. The ratio of the number of molecules in compartments I and II is not equal to:

a. 1 : 16
b. 6 : 1
c. 4 : 1
d. 1 : 4
Answer : A, B, C

Question. Consider a collision between an oxygen molecule and a hydrogen molecule in mixture of oxygen and hydrogen, kept at room temperature. Which of the following are possible?
a. The kinetic energies of both the molecules shall increases
b. The kinetic energy of both the molecules shall decreases
c. The kinetic energy of the oxygen molecule increases and that of the hydrogen molecule decreases
d. The kinetic energy of the hydrogen molecule increases and that of the oxygen molecule decreases
Answer : C, D

Question. For a jar containing H2 and He gases which of the following statements are correct:
a. The molecules of both gases have same average translational kinetic energy
b. The molecules of both gases have same average energy
c. Hydrogen molecules have greater average energy than the helium molecules
d. The molecules of both gases have same average speed
Answer : A, C

Question. Two identical containers A and B have friction ales pistons. They contain the same volume of an ideal gas at the same temperature. The mass of the gas in A is mA and that in B is B_m. The gas in each cylinder is now allowed to expand isothermally to double the initial volume. The change in pressure in A and B are found to be ΔP and 1.5 ΔP respectively. Which of the following will not be true?
a. 4m_A = 9 m_B
b. 2m_A = 3 m_B
c. 3m_A = 2 m_B
d. 9m_A = 4 m_B
Answer : A, B, D

Question. Let , v v_rms and v_p respectively denote the mean speed, root mean square speed and most probable speed of the molecules ion an ideal monoatomic gas at absolute temperature T. The mass of a molecule in m. Then: 
a. no molecule can have a speed greater than √2v_rms 
b. no molecule can have speed less than v_p  / √2
c. p rms v < v < v
d. the average kinetic energy of a molecule is 3/4mv²_p
Answer : C, D

Question. Which of the following statement (s) is/are true regarding the Kinetic theory of gases?
a. The pressure of the gas is directly proportional to the average speed of the molecules
b. The root mean-square speed of the molecules is directly proportional to the pressure
c. The rate of diffusion is directly proportional to the average speed of the molecules
d. The average Kinetic energy per molecule is directly proportional to the absolute temperature
Answer : C, D

Question. According to Kinetic Theory of Gas which one of the following statement (s) is/are true?
a. Real gas behaves as ideal gas at high temperatures and low pressures
b. Liquid state of ideal gas is impossible
c. At any temperature and pressure ideal gas obeys the Boyle’s law and Charle’s law
d. The molecules of real gas do not exert any force on one another
Answer : A, B, C

Question. From the following statements concerning ideal gas at any given temperature T, select the correct one (s).
a. The coefficient of volume expansion at constant pressure is the same for all ideal gases
b. The average translational kinetic energy per molecule of oxygen gas is 3 kT, k being Boltzmann constant
c. The mean-free path of molecules increases with decrease in the pressure
d. In a gaseous mixture, the average translational kinetic energy of the molecules of each component is different
Answer : A, C

Question. Consider the quantity MkT/PV of an ideal gas, where M is the mass of the gas. It does not depend on the:
a. temperature of the gas
b. volume of the gas
c. pressure of the gas
d. nature of the gas
Answer : A, B, C

Question. The ratio of two specific heats C_P/C_V of CO is:
a. 1.33
b. 1.40
c. 1.29
d. 1.66
Answer : B, C

Question. C_V and C_p denote the molar specific heat capacities of a gas at constant volume and constant pressure, respectively. Then,
a. C_p – C_V is larger for a diatomic ideal gas than for a monoatomic ideal gas
b. C_p + C_V is larger for a diatomic ideal gas than for a monoatomic ideal gas
c. C_p / C_V is larger for a diatomic ideal gas than for a monoatomic ideal gas
d. C_p, C_V is larger for a diatomic ideal gas than for a monoatomic ideal gas
Answer : B, D

Question. The average translational energy and the rms speed of the molecules in a sample of oxygen gas at 300 K are 6.21 ×10^–21 J and 484 m/s respectively. Assuming ideal gas behaviour, the corresponding values at 600 K are not nearly.
a. 12.42 × 10^–21J, 968 m/s
b. 8.78 × 10^–21 J, 684 m/s
c. 6.21 × 10^–21 J, 968 m/s
d. 12.42 × 10^–21 J, 684 m/s
Answer : A, B, C

Question. According to kinetic theory of gases, 0K is that temperature at which:
a. pressure of ideal gas is zero
b. volume of ideal gas is zero
c. internal energy of ideal is zero
d. ideal gas liquifies
Answer : A, B, C

Question. Two identical containers each of volume V₀ are joined by a small pipe. The containers contain identical gases at temperature T₀ and pressure P₀. One container is heated to temperature 2T₀ while maintaining the other at the same temperature. The common pressure of the gas is P and n is the number of moles of gas in container at temperature 2T₀

Answer : B, C

Assertion and Reason 

Note: Read the Assertion (A) and Reason (R) carefully to mark the correct option out of the options given below:
a. If both assertion and reason are true and the reason is the correct explanation of the assertion.
b. If both assertion and reason are true but reason is not the correct explanation of the assertion.
c. If assertion is true but reason is false.
d. If the assertion and reason both are false.
e. If assertion is false but reason is true.

Question. Assertion: The root mean square and most probable speeds of the molecules in a gas are the same.
Reason: The Maxwell distribution for the speed of molecule in a gas is symmetrical.
Answer : D

Question. Assertion: A hydrogen filled balloon stops rising after it has attained a certain height in the sky.
Reason: The atmosphere pressure decreases with height and becomes zero when maximum height is attained by hydrogen balloon.
Answer : C

Question. Assertion: In pressure-temperature (P – T) phase diagram of water, the slope of melting curve is found to be negative.
Reason: Ice contracts on melting to water.
Answer : A

Question. Assertion: For an ideal gas, at constant temperature, the product of the pressure and volume is constant.
Reason: The mean square velocity of the molecules is inversely proportional to mass.
Answer : B

Question. Assertion: The root mean square velocity of molecules of a gas having Maxwellian distribution of velocities is higher than their most probable velocity, at any temperature.
Reason: A very small number of molecules of gas possess very large velocities.
Answer : C

Question. Assertion: Mean free path of gas molecules, varies inversely as density of the gas.
Reason: Mean free path of gas molecules is defined as the average distance travelled by a molecule between two successive collisions.
Answer : B

Question. Assertion: The total translational kinetic energy of all the molecules of a given mass of an ideal gas is 1.5 times the product of its pressure and its volume.
Reason: The molecules of a gas collide with each other and the velocities of the molecules change due to the collision.
Answer : B

Question. Assertion: For a gas atom, the number of degrees of freedom is 3.
Reason: (C_p/C_v) = γ
Answer : B

Question. Assertion: The root mean square and most probable speeds of the molecules in a gas are the same.
Reason: The Maxwell distribution for the speed of the molecules in gas is symmetrical.
Answer : D

Question. Assertion: At room temperature, water does not sublimate from water to steam.
Reason: The critical point of water is much above the room temperature.
Answer : A

Comprehension Based

Paragraph –I

An gas which obeys gas laws is called can ideal gas. With your knowledge of gas laws obeyed by an ideal gas answer the following questions.

Question. Which of the following graphs is correct for an ideal gas at constant pressure?

Answer : B

Question. The V-T graph for an ideal gas is:

a. P₁ > P₂
b. P₁ < P₂
c. P₁ = P₂
d. P₁ ≥ P₂
Answer : D

Question. An ideal gas is at temperature T and volume V. It is volume is increased by ΔV due to increase in temperature ΔT at constant pressure then if y = 1/V ΔV/ΔT, then T-Y graph is:

Answer : C