Q1. (a) Explain the following term with ONE example in your daily life. (1) Equimolar counterdiffusion (7 marks) A diffuse through non-diffusing B (4 marks) (b) Ethanol vapor is absorbed from binary gas mixture of ethanol vapor and water vapor using a nonvolatile solvent in which ethanol is soluble but water is not The total pressure is 760 mmHg. The ethanol vapor is diffusing through a film of ethanol-water vapor mixture of 0.2 mm thick. The mole percent of the ethanol in the vapor at point 1 at one boundary of the film is 70%, and at the other boundary at point 2 is 20%. The diffusivity of ethanol-water vapor mixtures at 25 C and 1 atm is 0.135 cm-/s. The area of the film is 10 m. Given that the molecular weight of ethanol is 46.07 kg/kg mol. Calculate the rate of diffusion of ethanol vapor in kg/h if: (1) The temperature is 25 C (10 marks) (ii) The temperature is 70 C (8 marks) (c) Two bulbs are connected by a straight tube, 0.002 m in diameter and 0.3 m in length. Initially the bulb at point I contains N, and the bulb at point 2 contains H2. The temperature and pressure are maintained constant at 25 C and 1 atm. The partial pressure of Na gas at point of the tube is 0.90 atm and at point 2 is 0.30 atm. If the diffusion coefficient is 0.784 cmls, determine: (i) The diffusion rate of Na gas in kg mol/s for equimolar counterdiffusion. (4 marks) (ii) The velocity of N2 gas relative to stationary point (m/s) at point 2. (6 marks) ( (d) 100 kg of acetone (A)-water (B) solution at 25C is in contact at one surface with an organic solvent in which acetone is soluble and water is insoluble. The solution forms a stagnant film of 2 mm thick. The concentration of acetone at point 1 is 15 wt% and the solution density (P.) is 988.69 kg/m. At point 2, the concentration of acetone is 8 wt% and the solution density (P2) is 994.32 kg/m. The diffusivity of acetone in water 1.28 * 10 cm-/s. The molecular weight of acetone is 58.08 g/mol and water is 18.02 g/mol. Calculate the flux NA in kg mol/s.m at steady state. (15 marks) (e) Hydrogen diffuses through a polyethylene membrane at 25 C. The pressures on the sides of the membrane are 6 MPa and 350 kPa. Diffusivity and permeability data are given in Table 1. If the hydrogen flux is to be 0.34 kg mol/m.h, determine the thickness of the membrane in um. (6 marks)