Q. 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?

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Q. Sublimation of a long cylinder made of napthelene occurs in a large volume of stagnant air. The time required for its complete sublimation is

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

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Q. 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.

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Q. 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.

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Q. 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?

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Q. 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.

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Q. 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.

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

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Q. 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?

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

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Q. Find the number of stages.

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Q. Find the process.

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Q. From the figure find the extract positions.

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Q. Find the number of stages.

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Q. Look at the operating line which represents?

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Q. Can we able to find the extract at the second stage with the known values of E1, R1, S2.

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Q. Find the value of extract percentage in the second stage.

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