Topic: UNIT 6: Gaseous State (Test 1)

Topic: UNIT 6: Gaseous State
Q.1
Gases deviate from ideal behavior at high pressure. Which of the following statement(s) is correct for non-ideality?
A. at high pressure the collision between the gas molecule become enormous
B. at high pressure the gas molecules move only in one direction
C. at high pressure, the volume of gas become insignificant
D. at high pressure the intermolecular interactions become significant
Explaination / Solution:
No Explaination.

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Q.2
Rate of diffusion of a gas is
A. directly proportional to its density
B. directly proportional to its molecular weight
C. directly proportional to its square root of its molecular weight
D. inversely proportional to the square root of its molecular weight
Explaination / Solution:
No Explaination.

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Q.3
Which of the following is the correct expression for the equation of state of van der Waals gas?
A. B. C. D. Explaination / Solution:
No Explaination.

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Q.4
When an ideal gas undergoes unrestrained expansion, no cooling occurs because the molecules
A. are above inversion temperature
B. exert no attractive forces on each other
C. do work equal to the loss in kinetic energy
D. collide without loss of energy
Explaination / Solution:
No Explaination.

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Q.5
Equal weights of methane and oxygen are mixed in an empty container at 298 K. The fraction of total pressure exerted by oxygen is
A. 1/3
B. 1/2
C. 2/3
D. 1/3 × 273 × 298
Explaination / Solution:

mass of methane

= mass of oxygen = a

number of moles of methane = a/16

number of moles of Oxygen = a/32

mole fraction of Oxygen =

=[a/32] / [{a/16} + {a/32{ ]

= [a/32] / [3a/32]

=1/32

Partial pressure of oxygen

= mole fraction Total Pressure

=1/3 P

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Q.6
The temperatures at which real gases obey the ideal gas laws over a wide range of pres-sure is called
A. Critical temperature
B. Boyle temperature
C. Inversion temperature
D. Reduced temperature
Explaination / Solution:

The temperature at which real gases obey the ideal gas laws over a wide range of pressure is called Boyle temperature

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Q.7
In a closed room of 1000 m3 a perfume bottle is opened up. The room develops a smell. This is due to which property of gases?
A. Viscosity
B. Density
C. Diffusion
D. None
Explaination / Solution:
No Explaination.

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Q.8
A bottle of ammonia and a bottle of HCl connected through a long tube are opened simultaneously at both ends. The white ammonium chloride ring first formed will be
A. At the center of the tube
B. Near the hydrogen chloride bottle
C. Near the ammonia bottle
D. Throughout the length of the tube
Explaination / Solution:

Rate of diffusion α 1/√m

mNH3 = 17 ; mHCl = 36.5

γNH3 > γHCl

Hence white fumes first formed near hydrogen chloride

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Q.9
The value of universal gas constant depends upon
A. Temperature of the gas
B. Volume of the gas
C. Number of moles of the gas
D. units of Pressure and volume
Explaination / Solution:
No Explaination.

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Q.10
The value of the gas constant R is
A. 0.082 dm3atm.
B. 0.987 cal mol-1 K-1
C. 8.3 J mol-1K-1
D. 8 erg mol-1K-1