NEET Chemistry Gaseous State MCQs Set D

Question. The energy absorbed by each molecule (A₂) of a substance is 4.4×10^–19 J and bond energy per molecule is 4.0 ×10^–19 J. The kinetic energy of the molecule per atom will be 
(a) 4.0×10^–20 J
(b) 2.0 ×10^–20 J
(c) 2.2×10^–19 J
(d) 2.0×10^–19 J

Answer: B

Question. What is the dominant intermolecular force or bond that must be overcome in converting liquid CH₃OH to a gas? 
(a) London dispersion force
(b) Hydrogen bonding
(c) Dipole-dipole interaction
(d) Covalent bonds

Answer: B

Question. If a gas expands at constant temperature, it indicates that
(a) kinetic energy of molecules decreases
(b) pressure of the gas increases
(c) kinetic energy of molecules remains the same
(d) number of the molecules of gas increases

Answer: C

Question. Which of the following statements is not correct? 
(a) The fraction of the total volume occupied by the atoms in a primitive cell is 0.48
(b) Molecular solids are generally volatile
(c) The number of carbon atoms in an unit cell of Diamond is 4
(d) The number of Bravais lattices in which a crystal can be categorized is 14

Answer: A

Question. A solution has a 1 : 4 mole ratio of pentane to hexane. The vapour pressures of the pure hydrocarbons at 20ºC are 440 mmHg for pentane and 120 mmHg for hexane. The mole fraction of pentane in the vapour phase would be 
(a) 0.200
(b) 0.478
(c) 0.549
(d) 0.786

Answer: B

Question. The work done during the expansion of a gas from a volume of 4 dm3 to 6 dm3 against a constant external pressure of 3 atm is (1 L atm = 101.32 J) 
(a) – 304 J
(b) – 6 J
(c) – 608 J
(d) + 304 J

Answer: C

Question. The maximum number of molecules is present in 
(a) 10 g of O₂ gas
(b) 15 L of H₂ gas at STP
(c) 5 L of N₂ gas at STP
(d) 0.5 g of H₂ gas

Answer: B

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. Two gases A and B having the same volume diffuses 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. A gaseous mixture was prepared by taking equal mole of CO and N₂. If the total pressure of the mixture was found 1 atmosphere, the partial pressure of the nitrogen (N₂) in the mixture is 
(a) 0.5 atm
(b) 0.8 atm
(c) 0.9 atm
(d) 1 atm

Answer: A

Question. The pressure exerted by 6.0g 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 JK^–1 mol^–1)
(a) 215216 Pa
(b) 13409 Pa
(c) 41648 Pa
(d) 31685 Pa

Answer: C

Question. A bubble of air is underwater at temperature 15°C and the pressure 1.5 bar. If the bubble rises to the surface where the temperature is 25°C and the pressure is 1.0 bar, what will happen to the volume of the bubble? 
(a) Volume will become greater by a factor of 2.5
(b) Volume will become greater by a factor of 1.6
(c) Volume will become greater by a factor of 1.1
(d) Volume will become smaller by a factor of 0.70

Answer: B

Question. Equal masses of H₂, O₂  and methane have been taken in a container of volume V at temperature 27°C in identical conditions. The ratio of the volumes of gases H₂ : O₂ : methane would be 
(a) 16 : 1 : 2
(b) 8 : 1 : 2
(c) 8 : 16 : 1
(d) 16 : 8 : 1

Answer: A

Question. A mixture of gases contains H₂ and O₂ gases in the ratio of 1 : 4 (w/w). What is the molar ratio of the two gases in the mixture? 
(a) 16 : 1
(b) 2 : 1
(c) 1 : 4
(d) 4 : 1

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 one-half of the hydrogen to escape? 
(a) 1/8
(b) 1/4
(c) 3/8
(d) 1/2

Answer: A

Question. A 20 litre container at 400 K contains CO₂ (g) at pressure 0.4 atm and an excess of SrO (neglect the volume of solid SrO). The volume of the container is now decreased by moving the movable piston fitted in the container. The maximum volume of the container, when pressure of CO₂ attains its maximum value, will be: (Given that: SrCO₃ (s) SrO(s) CO₂ (g) , Kp = 1.6 atm)
(a) 10 litre
(b) 4 litre
(c) 2 litre
(d) 5

Answer: D

AIIMS

Question. Dominance of strong repulsive forces among the molecules of the gas (Z = compressibility factor)
(a) Depends on Z and indicated by Z = 1
(b) Depends on Z and indicated by Z > 1.
(c) Depends on Z and indicated by Z < 1
(d) Is independent of Z

Answer: C