Briefly explain the difference between mass transfer coefficient and diffusion coefficient using a suitable diagram (only a brief sketch) of the diffusion layer model for a reaction between aqueous species and a solid (see lecture slides) (a) (b)assume that the mass transfer of a controls the rate of reaction between a and b at each of the three interphases (i), (ii) and (iii) shown below. comment with reasons (one sentence only in each case) regarding the phase through which the transfer of a will control the reaction rate (solid, gas or aqueous) (iii) organic (b) aqueous (a) solid (b) gas (a) aqueous (a) aqueous (b) (c) nickel dissolves from millerite (nis) in an oxygenated sulfuric acid solution at 80 °c. list the important steps, which may control the leaching of nickel from the suspended nis particles in this solution according to the reaction