Pure aniline is evaporating through a stagnant air film of 1 mm thickness at 300 K and a total pressure of 100 KPa. The vapor pressure of aniline at 300 K is 0.1 KPa. The total molar concentration under these conditions is 40.1 mole/m3. The diffusivity of aniline in air is 0.74 × 10-5m2/s. The numerical value of mass transfer co-efficient is 7.4 × 10-3. Its units are_______________________?

Related Mcqs:

1. A car tyre of volume 0.057 m3 is inflated to 300 kPa at 300 K. After the car is driven for 10 hours, the pressure in the tyre increases to 330 kPa. Assume air is an ideal gas and Cv for air is 21 J/mole.K. The change in the internal energy of air in the tyre in J/mole is__________________?

   A. 380
   B. 630
   C. 760
   D. 880

2. A vessel of volume 1000 m3 contains air which is saturated with water vapour. The total pressure and temperature are 100 kPa and 20°C respectively. Assuming that the vapour pressure of water at 20°C is 2.34 kPa, the amount of water vapour (in kg) in the vessel is approximately ?

   A. 17
   B. 20
   C. 25
   D. 34

3. Saturated solution of benzene in water is in equilibrium with a mixture of air and vapours of benzene and water at room temperature and pressure. Mole fraction of benzene in liquid is xB and the vapour pressures of benzene and water at these conditions are pv B and pv w respectively. The partial pressure of benzene in air-vapour mixture is_________________?

   A. PvB
   B. xB.PvB
   C. (Patm – Pvw)xB
   D. xB.Patm

4. Pure oxygen is mixed with air to produce an enriched air containing 50 volume % of oxygen. The ratio of moles of air to oxygen used is_________________?

   A. 1.72
   B. 0.58
   C. 0.5
   D. 0.2

5. The boiling points for pure water and pure toluene are 100°C and 110.6°C respectively. Toluene and water are completely immiscible in each other. A well agitated equimolar mixture of toluene and water are prepared. The temperature at which the above mixture will exert a pressure of one standard atm. is___________________?

   A. Less than 100°C
   B. 100°C
   C. Between 100 and 110°C
   D. 110.6°C

6. Pick out the wrong unit conversion of mass transfer co-efficient?

   A. 1 lb/hr.ft3.atm. = 4.8182 kg/hr.m2.bar
   B. 1 kg/hr.m2.atm= 0.98687 kg/hr. m .bar
   C. 1 lb/hr.ft2 = 4.8823 kg/hr.m2
   D. 1 kg/hr.m2 = 4.8823 lb/hr.ft2

7. One kg of saturated steam at 100°C and 1.01325 bar is contained in a rigid walled vessel. It lias a volume of 1.673 m3. It cools to 98°C; the saturation pressure is 0.943 bar ; one kg of water vapour under these conditions has a volume of 1.789 m3. The latent heat of condensation (kJ/kg-1 ) under these conditions is___________________?

   A. 40732
   B. 2676
   C. 2263
   D. 540

8. Under conditions of equal reduced pressure and equal reduced temperature, substances are said to be in the ‘corresponding states’. At equal reduced conditions i.e., at the corresponding state, the ____________ of different gases are nearly the same?

   A. Compressibility
   B. Molecular weight
   C. Humidity
   D. None of these

9. Air at a temperature of 20°C and 750 mm Hg pressure has a relative humidity of 80%. What is its percentage humidity? Vapour pressure of water at 20°C is 17.5 mm Hg?

   A. 80.38
   B. 80
   C. 79.62
   D. 78.51

10. For water evaporating into unsaturated air under adiabatic conditions and at constant pressure, the ____________ remains constant throughout the period of vaporisation ?

    A. Dry bulb temperature
    B. Wet bulb temperature
    C. Humidity
    D. Relative saturation