The main goal of this paper is to demonstrate the validity of the Maxwell-Stefan theory for the description of liquid phase mass transport processes in a binary mixture. To critically test this theory absorption experiments of ammonia in water were conducted in a stirred cell. The flux model developed by Frank et al. (1995a) has been extended to a dynamic reactor model taking thermodynamic non-idealities and concentration and temperature dependent physical parameters into account. Calibration of the stirred cell was achieved on basis of carbon dioxide absorption experiments in water. By using the Maxwell-Stefan flux expressions instead of Fick's first law, and therefore accounting for the convective transport contributions, the deviation between theory and experiment reduces from 20-30% to 5-10%.