Question 1. For a steady state equimolar counter diffusion of A and B. The N flux of A is ________

Question 2. In sulphuric acid plants dry air is used for burning of sulphur. Air is dried in contact with concentrated Sulphuric acid. Moisture diffuses through a layer of air, reaches the surface and gets absorbed in it. Here air is said to be non-diffusing were as moisture is diffusing. Which of the following statements are correct?

Question 3. The value of a ratio of N flux of A to the total N flux for a steady state equimolar counter diffusion is

Question 4. A mixture of 60% hydrogen and 40% oxygen is blowing over a pan of water at 1atm pressure. The bulk gas temperature is 30°C and the water temperature is 20°C. The vapor pressure of water at this temperature is 17.53mm Hg. The concentration of moisture in the bulk gas is negligible and the diffusivity values are DO₂-H₂O=0.357cm²/s, DH₂-H₂O=0.972cm²/s at 34°C and DH₂-O₂=0.891cm²/s at 43°C.
What is the value of the flux (kmol/m³.s) of water vapor through a stagnant film of estimated thickness 1.5mm on the water surface?

Question 5. Consider steady-state equimolar counterdiffusion through the converging-diverging tube. Given: r₁=1cm; r₂=2cm; Nᴀ=10⁻⁶ kmol/m².s at the vessel 1 end of the tube. The rate of transport of B at the vessel 2 end of the tube is

Question 6. The molar average velocity of the components in a binary mixture in which they are in equimolar counter diffusion is

Question 7. Find the number of stages.

Question 8. In an accident a container containing ethanol(s.g 0.789) falls down in a room of dimension 1*1*2(all in m). Ethanol forms a layer of 2mm. Ethanol vaporizes and diffuses through a stagnant film of air of thickness 2.5mm. What will be the time required for the water layer to disappear completely, if the floor has micro pores and water penetrates the floor at a constant rate of 0.1kg/m²h. The diffusivity of ethanol in air is 2.567*10⁻⁵ m²/s. The total pressure is 1.013 bar and the pressure of ethanol in bulk air is 0.02244 bar and at the ethanol-air interface is 0.02718bar. The temperature is 25.2°C.

Question 9. A cylinder of sulfur is kept in a large volume of stagnant air for sublimation. How much time will be required for its complete sublimation?

Question 10. For a gas mixture (A+B) equimolar counterdiffusion takes place. Which among the following statements are correct for molar flux?