CBSE Class 11 Chemistry States of Matter Assignment

Question. Dipole-induced dipole interactions are present in which of the following pairs?
(a) HCl and He atoms
(b) SiF₄ and He atoms
(c) H₂O and alcohol
(d) Cl₂ and CCl₄
Answer. A

Question. Which one of the following is the correct order of interactions?
(a) Covalent < hydrogen bonding < van der Waals’< dipole-dipole
(b) van der Waals’ < hydrogen bonding < dipoledipole< covalent
(c) van der Waals’ < dipole-dipole < hydrogen bonding < covalent
(d) Dipole-dipole < van der Waals’ < hydrogen bonding < covalent. 
Answer. B

Question. Which of the following statements is wrong for gases?
(a) Confined gas exerts uniform pressure on the walls of its container in all directions.
(b) Volume of the gas is equal to volume of container confining the gas.
(c) Gases do not have a definite shape and volume.
(d) Mass of a gas cannot be determined by weighing a container in which it is enclosed.
Answer. D

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. Pressure remaining the same, the volume of a given mass of an ideal gas increases for every degree centrigrade rise in temperature by definite fraction
of its volume at
(a) 0°C
(b) its critical temperature
(c) absolute zero
(d) its Boyle temperature.
Answer. A

Question. A mixture of N₂ and Ar gases in a cylinder contains 7 g of N2 and 8 g of Ar. If the total pressure of the mixture of the gases in the cylinder is 27 bar, the partial pressure of N₂ is [Use atomic masses (in g mol–1) : N = 14, Ar = 40]
(a) 9 bar
(b) 12 bar
(c) 15 bar
(d) 18 bar.
Answer. C

Question. The volume occupied by 1.8 g of water vapour at 374°C and 1 bar pressure will be [Use R = 0.083 bar L K^–1mol^–1]
(a) 96.66 L
(b) 55.87 L
(c) 3.10 L
(d) 5.37 L
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) 3/8
(b) 1/2
(c) 1/8
(d) 1/4 
Answer. C

Question. What is the density of N₂ gas at 227°C and 5.00 atm pressure? (R = 0.082 L atm K–1mol–1)
(a) 1.40 g/mL
(b) 2.81 g/mL
(c) 3.41 g/mL
(d) 0.29 g/mL
Answer. C

Question. 50 mL of each gas A and of gas B takes 150 and 200 seconds respectively for effusing through a pin hole under the similar conditions. If molecular mass of gas B is 36, the molecular mass of gas A will be
(a) 96
(b) 128
(c) 32
(d) 64 
Answer. None

Question. A certain gas takes three times as long to effuse out as helium. Its molecular mass will be
(a) 27 u
(b) 36 u
(c) 64 u
(d) 9 u 
Answer. B

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. A gaseous mixture was prepared by taking equal moles 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. 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 1.6.
(b) Volume will become greater by a factor of 1.1.
(c) Volume will become smaller by a factor of 0.70.
(d) Volume will become greater by a factor of 2.5.
Answer. A

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

Question. Which of the following mixtures of gases does not obey Dalton’s law of partial pressure?
(a) Cl₂ and SO₂
(b) CO₂ and He
(c) O₂ and CO₂
(d) N₂ and O₂
Answer. A

Question. At what temperature, the rate of effusion of N₂ would be 1.625 times than the rate of SO₂ at 50°C?
(a) 373°C
(b) 620°C
(c) 100°C
(d) 173°C 
Answer. C

Question. 50 mL of hydrogen diffuses out through a small hole of a vessel, in 20 minutes. The time taken by 40 mL of oxygen to diffuse out is
(a) 32 minutes
(b) 64 minutes
(c) 8 minutes
(d) 12 minutes 
Answer. B

Question. Under what conditions will a pure sample of an ideal gas not only exhibit a pressure of 1 atm but also a concentration of 1 mole litre–1?
(R = 0.082 litre atm mol^–1 deg^–1)
(a) At STP
(b) When V = 22.4 litres
(c) When T = 12 K
(d) Impossible under any conditions 
Answer. C

Question. The correct value of the gas constant ‘R’ is close to
(a) 0.082 litre-atmosphere K
(b) 0.082 litre-atmosphere K^–1 mol^–1
(c) 0.082 litre-atmosphere^–1 K mol^–1
(d) 0.082 litre^–1 atmosphere^–1 K mol
Answer. B

ONE MARK QUESTIONS

1. In terms of Charles laws explain why -273^oC is lowest possible temperature?

2. Using the equation of state PV=nRT show that at a given temperature, the density of a gas is proportional to pressure.

3. Critical temperature for carbon dioxide and methane are 31.1^oC and -81.9^oC respectively. Which of theses has stronger intermolecular forces and why?

4. Define Boyle point.

5. Molecule A is twice as heavy as the molecule B. which of these has higher kinetic energy at any temperature?

TWO MARKS QUESTIONS

1. Express the following in the units given in brackets.

a) 300cm of Hg [atmosphere]

b) 1bar [ kPa]

c) 500000 Pa [ bar]

d) 450mm of Hg [ Pa]

2. What type of intermolecular forces are existing between the following

i. HCl and H₂O

ii. F₂ molecule

iii. Br- and H₂O

iv. CO₂ and ammonia

3. Explain each of the following

i. Tyres of automobiles are inflated to lesser pressure in summer than in winter

ii. Glycerin is more viscous than water

4. A gas occupies 0.15dm³ when collected over water at 15^oC and 75cm of Hg. In the dry condition the same gas occupies 0.138dm³ at NTP. Calculate aqueous tension.