CBSE Class 11 Chemistry States of Matter MCQs Set C

Question: Average molar kinetic energy of CO and N₂ at same temperature is
a) KE₁ = KE₂
b) KE₁ > KE₂
c) KE₁ < KE₂
d) can’t say anything. Both volumes are not given. 
Answer: a

Question: At 25°C and 730 mm pressure, 380 mL of dry oxygen was collected. If the temperature is constant, what volume will the oxygen occupy at 760 mm pressure?
a) 569 mL
b) 365 mL
c) 265 mL
d) 621 mL 
Answer: b

Question: When is deviation more in the behaviour of a gas from the ideal gas equation PV = nRT?
a) At high temperature and low pressure
b) At low temperature and high pressure
c) At high temperature and high pressure
d) At low temperature and low pressure 
Answer: b

Question: At constant temperature, in a given mass of an ideal gas
a) the ratio of pressure and volume always remains constant
b) volume always remains constant
c) pressure always remains constant
d) the product of pressure and volume always remains constant.
Answer: d

Question: If P, V, M, T and R are pressure, volume, molar mass, temperature and gas constant respectively, then for an ideal gas, the density is given by
a) RT PM
b) P RT
c) M V
d) PM RT
Answer: d

Question: By what factor does the average velocity of a gaseous molecule increase when the temperature (in Kelvin) is doubled?
a) 2.0
b) 2.8
c) 4.0
d) 1.4
Answer: d

Question: Select one correct statement. In the gas equation, PV = nRT
a) n is the number of molecules of a gas
b) V denotes volume of one mole of the gas
c) n moles of the gas have a volume V
d) P is the pressure of the gas when only one mole of gas is present. 
Answer: c

Question: Which of the following statements regarding thermal energy is correct?
a) Thermal energy is the measure of average kinetic energy of the particles of the matter and is thus responsible for movement of particles.
b) Intermolecular forces tend to keep the moleculestogether but thermal energy of the molecules tends to keep them apart.
c) Three states of matter are the result of balance between intermolecular forces and the thermal energy of the molecules.
d) All of the options
Answer: d

Question: Root mean square velocity of a gas molecule is proportional to
a) m^1/2
b) m⁰
c) m^–1/2
d) m
Answer: c

Question: Induced dipole moment depend upon the I. dipole moment present in the permanent dipole. II polarisability of the electrically neutral molecules. Identify the correct option.
a) I is correct but II is wrong
b) I is wrong and II is correct
c) Both I and II are wrong
d) Both I and II are correct
Answer: d 

Question: 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. 
Answer: a

Question: At STP, 0.50 mol H₂ gas and 1.0 mol He gas
a) have equal average kinetic energies
b) have equal molecular speeds
c) occupy equal volumes
d) have equal effusion rates.
Answer: a

Question: A closed flask contains water in all its three states solid, liquid and vapour at 0°C. In this situation, the average kinetic energy of water molecules will be
a) the greatest in all the three states
b) the greatest in vapour state
c) the greatest in the liquid state
d) the greatest in the solid state.
Answer: b

Question: 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 repulsive forces are dominant
b) Z > 1 and attractive forces are dominant
c) Z > 1 and repulsive forces are dominant
d) Z < 1 and attractive forces are dominant.
Answer: d

Question: The average kinetic energy of an ideal gas, per molecule in S.I. units, at 25°C will be
a) 6.17 × 10^–20 J
b) 7.16 × 10^–20 J
c) 61.7 × 10^–20 J
d) 6.17 × 10^–21 J
Answer: d

Question: van der Waals’ 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
Answer: a

Question: 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 
Answer: a

Question: An ideal gas, obeying kinetic theory of gases cannot be liquefied, because
a) it solidifies before becoming a liquid
b) forces acting between its molecules are negligible
c) its critical temperature is above 0°C
d) its molecules are relatively small in size.
Answer: b

Question: 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 cooking in pressure cooker.
Answer: a

Question: A gas is said to behave like an ideal gas when the relation PV/T = constant. When do you expect a real gas to behave like an ideal gas?
a) When the temperature is low.
b) When both the temperature and pressure are low.
c) When both the temperature and pressure are high.
d) When the temperature is high and pressure is low.
Answer: d

Question: 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 ne- half of the hydrogen to escape?
a) 3/8
b) 1/2
c) 1/8
d) 1/4
Answer: c

Question: Which of the following is not a type of van der Waal's forces?
a) Dipole - dipole forces
b) Dipole - induced dipole forces
c) Ion - dipole forces
d) London forces
Answer: c

Question: Who proposed the concept of dispersion force ?
a) Heitler and London
b) van der Waal
c) Gay Lussac
d) Fritz London
Answer: d

Question: The interaction energy of London force is inversely proportional to sixth power of the distance between two interacting particles but their magnitude depends upon
a) charge of interacting particles
b) mass of interacting particles
c) polarisability of interacting particles
d) strength of permanent dipoles in the particles.
Answer: c

Question: 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 
Answer: b

Question: Dipole-dipole interaction is stronger than the London forces but is weaker than ion-ion interaction because
a) only partial charges are involved
b) only total charges are involved
c) both only partial charges are involved andonly total charges are involved
d) sometimes only partial charges are involved and sometimes only total charges are involved
Answer: a

Question: London forces are always ...I... and interaction energy is inversely proportional to the ...II... power of the distance between two interacting particles. Here, I and II refer to
a) I → repulsive, II → sixth
b) I → attractive,II → fourth
c) I → attractive,II → sixth
d) I → repulsive, II → fourth
Answer: c

Question: A gas such as carbon monoxide would be most likely to obey the ideal gas law at
a) low temperatures and high pressures
b) high temperatures and high pressures
c) low temperatures and low pressures
d) high temperatures and low pressures. 
Answer: d

 Question: The pressure exerted by 6.0 g of methane gas in a 0.03 m3 vessel at 129°C is (Atomic masses: C = 12.01, H = 1.01 and R = 8.314 J K–1 mol^–1)
a) 215216 Pa
b) 13409 Pa
c) 41648 Pa
d) 31684 Pa 
Answer: c