Question

I just did a lab on determination of an equilibrium constant through the reaction EtAc (aq) + H2O (sln) <-> EtOH (aq) +HAc (aq). For all initial concentrations, K was less than one. Which I know says that equilibrium favors reactants. One of the post lab questions is "After the titration of the solutions at equilibrium, how will the solution return to equilibrium? Which chemicals will increase and which will decrease? (Be careful with acetic acid) " I am not sure how to answer this

Answer 1

Hi you used ethyl acetate (EtAc) and hydrolyzed this ester into carboxylic acid (HAc - acetic acid) and an alcohol (ethyl alcohol - EtOH). Now you also used a strong base such as sodium hydroxide during hydrolysis of ester, otherwise esters will not hydrolyze itself as water is not sufficient power to do so. During hydrolysis NaOH also reacts with acetic acid and forms sodium acetate, now scenario suddenly changes with the combination of Acetic acid + sodium acetate - this combination works like a buffer (i think you are already familiar with buffers).

The combination of weak acid and its conjugate base now behaves as weak acidic buffer and the solution return to equilibrium. Acetic acid and sodium acetate will be in equilibrium with almost equal proportions as you have not provided how much exactly you have been taken ester and a strong base, so i cannot confirm Which chemicals will increase and which will decrease.

Hope this helped you!

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