States of Matter

For real gases van der Waals equation is written as (p + an2V2 )(V - nb) = nRT where a and b are van der Waals constants. Two sets of gases are (I) O2, CO2, H2 and He (II) CH4, O2 and H2 The gases given in set-I in increasing order of b and gases given in set-II in decreasing order of a, are arranged below. Select the correct order from the following

1. (I) He < H2 < CO2 < O2 (II) CH4 > H2 > O2
2. (I) O2 < He < H2 < CO2 (II) H2 > O2 > CH4
3. (I) H2 < He < O2 < CO2 (II) CH4 > O2 > H2
4. (I) H2 < O2 < He < CO2 (II) O2 > CH4 > H2

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

1. 96
2. 128.74
3. 20.25
4. 64.42

A bubble of air is underwater at temperature 15 and the pressure 1.5 bar. If the bubble rises to the surface where the temperature is 25 and the pressure is 1.0 bar, what will happen to the volume of the bubble?

1. Volume will become greater by a factor of 1.6.
2. Volume will become greater by a factor of 1.1.
3. Volume will become smaller by a factor of 0.70.
4. Volume will become greater by a factor of 2.5.

By what factor does the average velocity of a gaseous molecule increase when the temperature (in Kelvin) is doubled?

1. 2.0
2. 2.8
3. 4.0
4. 1.4

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

1. 50.00 u
2. 12.25 u
3. 6.50 u
4. 25.00 u

A gaseous mixture was prepared by taking equal moles of CO and N2. If the total pressure of the mixture was found to be 1 atmosphere, the partial pressure of the nitrogen (N2) in the mixture is

1. 0.5 atm
2. 0.8 atm
3. 0.9 atm
4. 1 atm

The pressure exerted by 6.0 g of methane gas in a 0.03 m3 vessel at 129 is (Atomic masses : C = 12.01, H = 1.01 and R = 8.314 J K-1 mol-1)

1. 215216 Pa
2. 13409 Pa
3. 41648 Pa
4. 31684 Pa

If a gas expands at constant temperature, it indicates that

1. kinetic energy of molecules remains the same
2. number of the molecules of gas increases
3. kinetic energy of molecules decreases
4. pressure of the gas increases

The surface tension of which of the following liquids is maximum ?

1. C2H5OH
2. CH3OH
3. H2O
4. C6H6

Van der Waals real gas acts as an ideal gas at which conditions?

1. High temperature, low pressure
2. Low temperature, high pressure
3. High temperature, high pressure
4. Low temperature, low pressure