The unit of van der Waals' constant 'b' is :

1. cm³ mol^-1

2. litre mol^-1

3. m³ mol^-1

4. All of these 

The mean free path ($\mathrm{\lambda }$) of a gas sample is given by:

1. $\lambda =\sqrt{2}\pi {\sigma }^{2}N$                               

2. $\lambda =1/\sqrt{2}\pi {\sigma }^{2}N$

3. $\lambda =\sqrt{2}\pi \mu {\sigma }^{2}N$                               

4. none of these

The unit of van der Waals' constant 'a' is:

1. atm litre² mol-²                       

2. dyne cm⁴ mol^-2

3. newton m⁴ mol^-2                     

4. All of the above           

The ratio a/b (the terms used in van der Waals' equation) has the unit-

1. atm litre mol^-1                           

2. atm dm³ mol^-1

3. dyne cm mol^-1                           

4. All of the above

Joule-Thomson coefficient ($\partial \mathrm{T}/\partial \mathrm{P}$)_H for an ideal gas is:

1. zero                                 

2. +ve

3. -ve                                   

4. none of these

The maximum deviation from ideal gas behaviour takes place -  

1. At high temperature and low pressure.

2. At low temperature and high pressure.

3. At high temperature and high pressure.

4. At low temperature and low pressure.

At relatively high pressure, van der Waals' equation reduces to-

1. PV = RT

2. PV = RT + a/v

3. PV = RT + Pb

4. PV = RT - a/V²

At STP, 0.50-mole H₂ gas and 1.0 mole He gas                                  

1. have equal average kinetic energies

2. have equal molecular speeds

3. occupy equal volumes

4. have equal effusion rates

Which is lighter than dry air?

1. Moist air                             

2. SO₂

3. Cl₂                                      

4. O₂

All the three states H₂O, i.e., the triple point for H₂O the equilibrium,

                       Ice $\rightleftharpoons$Water$\rightleftharpoons$Vapour exist at:

1. 3.85 mm and 0.0981 $°$C

2. 4.58 mm and 0.0098 $°$C

3. 760 mm and 0$°$C

4. none of the above