Although the gas-liquid reactions are employed in many industrial processes, this issue in the most of time is not included in the curriculum of Chemistry and Chemical Engineering courses. This work aims to propose the study of gas-liquid reaction for the degree course, considering a widespread system, the reaction of CO2-NaOH. A reaction mechanism was proposed considering all the intermediate reactions. For each point collected in the outlet solution all the products formed were quantified included residual absorbing solutions. The pH of the outlet solution received a special attention, because with this information was possible to study the controversy that there is in the state of art between some authors in consider the product of the reaction bicarbonate when under conditions of high temperature of or long exposure time of the liquid to gas. For this study was used a continuous stirred-tank reactor in which the gas phase simulate a bubble with a defined size in contact with the liquid phase. The experimental were made by trails under atmospheric pressure, using a feed mixture containing 76% to 69% of CO2 and 24% to 31% of synthetic air and as liquid solution sodium hydroxide 0.015 mol L-1, 0.08 mol L-1, 0.56 mol L-1 and 2.0 mol L-1. The experimental results obtained and the behavior of CO2-NaOH reaction were compared with the data reported in the literature and show a good performance.