500 mL of nitrogen at 27$°$C are cooled to -5$°$C at the same pressure. The new volume becomes-      

1. 326.32 mL                     

2. 446.66 mL

3. 546.32 mL                     

4. 771.56 mL

A gas cannot be liquefied if:

1. Forces of attraction are low under ordinary conditions

2. Forces of attraction are high under ordinary conditions

3. Forces of attraction are zero under ordinary conditions

4. Forces of attraction are either high or low under ordinary conditions

In the case of hydrogen and helium the van der Waals' forces are-

1. Strong                 

2. Very strong

3. Weak                   

4. None of the above

With the increase of pressure, the mean free path:

1. decreases                             

2. increases

3. becomes zero                       

4. remains the same

The compressibility factor of an ideal gas is:

1. zero                         

2. infinite

3. 1                               

4. -1

The correct value of the gas constant 'R' is close to 

1. 0.082 L atm K

2. 0.082 L atm K^-1 mol^-1

3. 0.082 L atm^-1 K mol^-1

4. 0.082 L^-1 atm^-1 K mol

The partial pressure of a dry gas is:

1. less than that of wet gas

2. greater than that of wet gas

3. equal to that of wet gas

4. none of the above

The number of molecules present in 1 mL of gas or vapor at STP is:

1. called Loschmidt's number

2. equal to 2.617 x 10¹⁹ per mL

3. both (1) and (2)

4. none of the above

 Air at sea level is dense. This is a practical application of:

1. Boyle's law                         

2. Charles' law

3. Avogadro's law                   

4. Dalton's law

In van der Waals' equation of state of the gas, the constant 'b' is a measure of:

1. Intermolecular collisions per unit volume

2. Intermolecular attraction

3. Volume occupied by molecules

4. Intermolecular repulsions