Question 51. A napthelene hemisphere is placed on a glass plate and a napthelene ball of identical diameter is kept suspended in the stagnant air in two large rooms. The respective shapes of the ball are maintained while they sublime and reduce in size. Which of the following statements are true in this connection?

Question 52. In a binary gas mixture containing A and B, If Nᴀ=-2Nв, what will be the expression for Nᴀ?

Question 53. A binary liquid mixture is separated by distillation process. The more volatile A vaporizes while less volatile B gets transported in opposite direction. Latent heat of vaporization of A and B is 0.5 unit and 1 unit respectively. What will be the relation between molar flux of A and B?

Question 54. 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. 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 55. Oxygen diffuses through a stagnant layer of air, 1mm thick, ambient temperature 28°C and 1atm total pressure. The partial pressure of oxygen on two sides of layer is P₁=0.9atm and P₂=0.1atm respectively. Calculate the value of Molar flux (in mol/m².s) with respect to an observer moving with molar average velocity. Calculate this value at the end of the path where P₂=0.1atm. Use R=8.205*10⁻⁵m³atmK⁻¹mol⁻¹.

Question 56. In order to prepare Lithium nitride, air is passed gently over a reactor. Suppose that Nitrogen diffuse to a length 5cm before getting reacted with Lithium. Nitrogen reacts with lithium quickly so that partial pressure of Nitrogen at that point is 0. Reactor is a cylinder of length 10cm and diameter 2cm. Assume air to be a mixture of Nitrogen and Oxygen only. The temperature is 298K and total pressure 1atm. Diffusivity of N₂ in O₂ is 2*10⁻⁵m²/s. Calculate the Molar flux (mol/m².s) of N₂ at a distance of 2.5cm from the top with respect to an observer moving with twice the mass average velocity a direction towards the liquid surface. (R=8.205*10⁻⁵m³atmK⁻¹mol⁻¹). Assume z=0 at the top of the reactor.

Question 57. Find the process.

Question 58. From the figure find the extract positions.

Question 59. Look at the operating line which represents?

Question 60. Find the number of stages.