Mass Transfer – Multiple Choice Questions (MCQs)

1. 1. What is the primary driving force for mass transfer?

   • A. Temperature difference
   • B. Pressure difference
   • C. Concentration difference
   • D. Velocity difference

2. 2. Which law describes steady-state molecular diffusion in a binary gas mixture?

   • A. Fick's First Law
   • B. Fick's Second Law
   • C. Newton's Law
   • D. Fourier's Law

3. 3. What does Fick's First Law relate?

   • A. Mass flux to concentration gradient
   • B. Heat flux to temperature gradient
   • C. Momentum flux to velocity gradient
   • D. Mass flux to pressure gradient

4. 4. In Fick's First Law, what is 'D_AB'?

   • A. Diffusion coefficient
   • B. Thermal conductivity
   • C. Viscosity
   • D. Heat transfer coefficient

5. 5. What is the unit of diffusion coefficient (D_AB) in SI units?

   • A. m/s
   • B. m²/s
   • C. mol/(m²·s)
   • D. kg/(m³·s)

6. 6. What is Fick's Second Law used to describe?

   • A. Unsteady-state molecular diffusion
   • B. Steady-state molecular diffusion
   • C. Turbulent diffusion
   • D. Convective mass transfer

7. 7. Which type of mass transfer involves the movement of molecules due to random molecular motion?

   • A. Convective mass transfer
   • B. Turbulent mass transfer
   • C. Molecular diffusion
   • D. Interphase mass transfer

8. 8. Which type of mass transfer involves the movement of molecules due to bulk fluid motion?

   • A. Molecular diffusion
   • B. Convective mass transfer
   • C. Interphase mass transfer
   • D. Diffusive mass transfer

9. 9. What is interfacial mass transfer?

   • A. Mass transfer within a single phase
   • B. Mass transfer across an interface between two phases
   • C. Mass transfer in turbulent flow
   • D. Mass transfer through a solid

10. 10. What is absorption?

    • A. Transfer of a solute gas into a liquid solvent
    • B. Transfer of a solute from liquid to gas
    • C. Separation of solids from liquids
    • D. Heat transfer between phases

11. 11. What is stripping?

    • A. Transfer of a solute from a liquid phase to a gas phase
    • B. Transfer of a solute from gas to liquid
    • C. Separation of solids from gases
    • D. Heat transfer without mass transfer

12. 12. Which equipment is commonly used for gas-liquid absorption and stripping?

    • A. Distillation column
    • B. Heat exchanger
    • C. Packed column
    • D. Centrifuge