(NRe . NSc) is termed in mass transfer operation as the ______________ number?

Related Mcqs:

1. (NSh/NRe.NSc) is termed in mass transfer operation as the __________________________?

   A. Stanton number
   B. Peclet number
   C. Thermal diffusivity
   D. Momentum diffusivity

2. According to Chilton-Colburn analogy for mass transfer, NSt.NSc 2/3 is equal to_________________?

   A. f
   B. f/2
   C. 2f
   D. 1/f

3. According to the film theory of mass transfer, the mass transfer co-efficient is proportional to (where, D = molecular diffusivity) ?

   A. D
   B. D2
   C. D0.5
   D. 1/D

4. For experimental determination of mass transfer co-efficient by wetted wall tower, the mass transfer area is___________________?

   A. Calculated
   B. Unknown
   C. Known
   D. Not required

5. JD factor for mass transfer is a function of Reynolds number. Mass transfer by molecular diffusion from a single drop to surrounding still air is given by___________________?

   A. Nsh = 2
   B. Nst = 2
   C. Nsc = 2
   D. None of these

6. The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, NPr = NSc = _________________?

   A. 1
   B. 0.5
   C. 10
   D. 0

7. A solid is being dried in the linear drying rate regime from moisture content Xo to XF. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture Xo. The drying time for M = (Ls/ARc) is (where, L = total mass of dry solid, A = total surface area for drying Rc = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids)) ?

   A. M(Xo – XF)
   B. M(Xo/XF)
   C. M ln(Xo/XF)
   D. MXo ln(Xo/XF)

8. A solid is being dried in the linear drying rate regime from moisture content Xo to XF. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture Xo. The drying time for M = (Ls/ARc) is (where, L = total mass of dry solid, A = total surface area for drying Rc = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids))_____________?

   A. M(Xo – XF)
   B. M(Xo/XF)
   C. M ln(Xo/XF)
   D. MXo ln(Xo/XF)

9. Mass transfer co-efficient ‘K’ according to penetration theory varies with mass diffusivity as____________________?

   A. D0.5
   B. D
   C. 1/D
   D. D1.5

10. H2S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H2S has to be reduced from 0.05 to 0.001 mole fraction in the gas side. The height of the tower (in meters) corresponding to an operating line given by, y = 5x + 0.001 is ______________________?

    A. 2.0
    B. 1.56
    C. 1.0
    D. 0.56