vii- Under which of the following conditions mass average velocity and molar average velocity are equal? a) In a very dilute solution b) If molecular weights of all the species are equal c) Always different d) In dilute solutions as well as in solutions in which all components have same molecular weights viii- For what kind of mixtures DAB=DBA holds? a) Ideal b) Real c) For both real and ideal d) This relation is never true. ix- Consider loss of ethanol vapor by diffusion from a half-filled open test tube. At what point in the diffusion path will the contribution of the bulk flow term to the molar flux be maximum? a) At the liquid-gas interface b) In the bulk liquid c) In the bulk gas d) None of the mentioned x - For a component A of a mixture, concentration as a function of x is given: CAA=5e10x(x is in cm and CA in mol/liter) If the diffusivity of A in the mixture is 2.567105m2/s, then the value of diffusion velocity (m/s) of the component A at the point x=0 is: a) 0.2567 b) 2.567 c) 0.0025 d) 3.541