Reactions with a Finite Velocity

For reactions in this regime, no general expressions can be derived for the diffusion flux, Na, through the gas and liquid films. Chemical reactions proceed in the liquid film and the following conditions are valid for diffusion fluxes through the gas and liquid films  

The first condition. Equation 7.71, states that the diffusion flux for component A in the liquid phase changes because of the reaction taking place in the liquid film. For the gas-liquid equilibrium at the interface, the following ratio is valid  

The transport equation for component A must be solved separately for each type of reaction kinetics. An analytical solution for Equation 7.52 is possible in some special cases. The liquid film must, however, be considered as isothermal, this being a quite reasonable assumption. 

Let us now consider an analytical solution for the mass balance equation of the liquid film 

By integrating Equation 7.76 twice, the concentration profiles for component A in the liquid film are obtained  

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