States of Matter

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?

1. NH3
2. H2
3. O2
4. CO2

The correction factor ‘a’ to the ideal gas equation corresponds to

1. density of the gas molecules
2. volume of the gas molecules
3. electric field present between the gas molecules
4. forces of attraction between the gas molecules

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?

1. 3/8
2. 1/2
3. 1/8
4. 1/4

A gas such as carbon monoxide would be most likely to obey the ideal gas law at

1. low temperatures and high pressures
2. high temperatures and high pressures
3. low temperatures and low pressures
4. high temperatures and low pressures

Dipole-induced dipole interactions are present in which of the following pairs

1. HCl and He atoms
2. SiF4 and He atoms
3. H2O and alcohol
4. Cl2 and CCl4

Maximum deviation from ideal gas is expected from

1. CH4(g)
2. NH3(g)
3. H2(g)
4. N2(g)

What is the density of N2 gas at 227 C and 5.00 atm pressure? (R = 0.082 L atm K-1 mol-1)

1. 1.40 g/L
2. 2.81 g/L
3. 3.41 g/L
4. 0.29 g/L

A certain gas takes three times as long to effuse out as helium. Its molecular mass will be

1. 27 u
2. 36 u
3. 64 u
4. 9 u

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