Component A is diffusing in a medium B. The flux NA relative to a stationary point is equal to the flux due to molecular diffusion, if____________________?

Related Mcqs:

1. The diffusivity, DAB (for component A diffusing in B) is equal to the diffusivity DBA (for component B diffusing in A) for a binary mixture of________________?

   A. Newtonian liquids
   B. Non-Newtonian liquids
   C. Ideal gases
   D. Real gases

2. Relative volatility varies with the concentration of component for an ideal solution. The relative volatility of a binary mixture may be defined as the ratio of vapor pressure of component ‘A’ to that of component ‘B’, when_________________?

   A. Only vapor phase follows Raoult’s law
   B. Only liquid phase obeys Dalton’s law
   C. Liquid phase obeys Dalton’s law and vapor phase obeys Raoult’s law
   D. Vapor phase obeys Dalton’s law and liquid phase obeys Raoult’s law

3. Experiments were conducted to determine the flux of a species A in a stagnant medium across a gas-liquid interface. The overall mass transfer co-efficient based on the liquid side for dilute systems for the above was estimated to be 4 × 10-3 kg mole/m2.s. The equilibrium data for the system is given as y = 2x. The flux across the interface (in kg mole/m2 .s) for bulk concentrations of A in gas phase and liquid phase as y = 0.4 and x = 0.01 respectively is _________________________?

   A. 5.6 × 10-4
   B. 8.5 × 10-4
   C. 5.6 × 10-3
   D. 8.5 × 10-3

4. The relation among various mass transfer co-efficients (M.T.C) for ideal gases is given by (where, Kc & Km are M.T.C. for equimolar counter diffusion with concentration & mole fraction respectively as the driving force. and, Kp= M.T.C. for diffusion of a gas through a stagnant inert gas with pressure as driving force) ?

   A. Kc = Kp = Km
   B. Kc = Kp/RT = Km . RT/P
   C. Kc = Kp . RT = Km . RT/p
   D. None of these

5. Ordinary diffusion process is also called ______________ diffusion?

   A. Pressure
   B. Thermal
   C. Concentration
   D. Forced

6. The value of NA/(NA + NB) for steady state molecular diffusion of gas ‘A’ through nondiffusing gas ‘B’ is____________________?

   A. 1
   B. ∞
   C. 0.5
   D. 2

7. 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

8. Molecular diffusion is caused by the________________?

   A. Transfer of molecules from low concentration to high concentration region
   B. Thermal energy of the molecules
   C. Activation energy of the molecules
   D. Potential energy of the molecules

9. The partial pressure distribution of an ideal gas diffusing through another stagnant ideal gas at steady state follows a/an _________________ law?

   A. Exponential
   B. Parabolic
   C. Linear
   D. Cubic

10. The diffusion co-efficient in m2/s. of acetic acid in benzene (liquid in liquid) is___________________?

    A. 2.09 × 10-4
    B. 2.09 × 10-5
    C. 2.09 × 10-9
    D. 2.09 × 10-12