viveklib04

I am facing a problem on transport phenomena. Can anyone help me to solve this problem. I would really appreciate it. Its little urgent. I know that i have to use shell mass balance to start the problem but how to proceed further is what making me confused.

In a beaker, a solid sphere of substance A is suspended and dissolving in the liquid B in a steady state, isothermal flow system. Above the liquid, there is gas C, which diffuse into liquid B and reacts simultaneously and irreversibly with A: A+C-->P. The liquid consists primarily of B and C
(1) develop an expression for the dissolution rate of A and find the reaction front location
(2) Show by quasi-steady-state condition how to calculate the gradual decrease in diameter of the sphere as A dissolves