Suppose molecular diffusion along coordinate x can be characterized by diffusion coefficient D ~V

where l is the characteristic displacement step length and v the frequency of displacements attempted at random in positive or negative direction. For a given solute, the average step length 1=0.5 and displacement frequency vat 25 C is ~ 10-2 5-2. Estimate : a) the solute diffusion coefficient D at 25C b) the solute friction coefficient in the solution c) liquid viscosity if solute molecules are of spherical shape with radius a = 2.0 . d) How far (in 3 dimensional space) does a molecule diffuse in an hour? e) Bonus question ( 5 points ) Write an expression for the percentage of molecules, which after time t still remain within distance d or closer to their initial position along coordinate x, x=0. f) Bonus question ( 5 points ) How does the expression change in case of diffusion in 3- dimensions