Gas A is absorbed by a stationary liquid solvent S, the latter containing solute B. Species A reacts with B in an instantaneous irreversible reaction (A+B ?P). A and B are present is S in low concentrations. There will be a plane parallel to the liquid-vapor interface at a distance zR, which separates the region containing no A from the containing no B. Obtain expression for the concentration profiles for A and B knowing that zR is a function of time. List down the boundary conditions knowing that at z=0, CA=CA0, at z ? ?, CB=CB?, at t=0, CB= CB?, where CB? is the original concentration of B, and CA0 is the solubility concentration of A is S.