FINDING EQUILIBRIUM CONSTANT VALUES FOR THE ETHANOL-ACETIC ACID REACTION

Abstract

The ethanol-acetic acid reaction is often used in first-year chemistry classes to illustrate the importance of a catalyst and what occurs at chemical equilibrium. The impact of adding different catalysts and the time required for the reaction mixtures to reach equilibrium were studied. In all cases, 0.30 moles of ethanol and 0.30 moles of acetic acid were used. It is concluded that students may learn several things from this reaction. Four of these are: 1) the importance of adding a catalyst, 2) how the concentration of reactants decrease and products increase with time, 3) how to use titrations to measure the concentration of the remaining acetic acid and to use this to determine the concentration of the ethanol and ester concentrations and 4) how to measure an equilibrium constant. This reaction has the added benefit of allowing students to use titrations to track the decrease in reactant concentration with time. In one trial, initial product (ester) molar concentrations of 6.2, 6.9, and 6.9 were computed for one, two, and three weeks after the catalyst was added, yielding an equilibrium constant of 2.0