Which is lighter than dry air?

1. Moist air                             

2. SO₂

3. Cl₂                                      

4. O₂

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 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 beans are cooked in pressure cooker, because -                                   

1. Boiling point increases with increasing pressure

2. Boiling point decreases with increasing pressure

3. Extra pressure of pressure cooker softens the beans

4. Internal energy is not lost while cooking in pressure cooker

 The compressibility factor for H₂ and He is usually:

1. >1                                     

2. =1

3. <1                                     

4. either of these

Boyle's law is applicable in :

1. Isobaric process

2. Isochoric process

3. Isothermal process

4. Adiabatic process

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 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

600 cc of a gas at a pressure of 750 mm is compressed to 500 cc. Taking the temperature to remain constant, the increase in pressure is:                                         

1. 150 mm                       

2. 250 mm

3. 350 mm                      

4. 450 mm

An ideal gas expands according to PV=constant. On expansion, the temperature of the gas:

1. Will rise.

2. Will drop.

3. Will remain constant.

4. Cannot be determined because the external pressure is not known.