I did an experiment to study the effects of changes in conditions on an equilibrium system. The first system was the dissociation of acetic acid.

Question

HC2H3O2 -> H^+^ + C2H3O2^-^
<-

We had to add 2mL of acetic acid into a test tube and we had to test the pH of the solution and record the color.

The solution was clear at first and then on the indicator paper the color was red with a pH of 4.

Then to this solution we added solid NaC2H3O2 and tested the pH again. This time the pH was 6 and the color was orange.

The question that I have to answer is did the equilibrium shift and in which direction?

The equilibrium did shift and I think that it shifted towards the reactant side. This would then be an endothermic process because products were removed??

Also, how did the pH of the solution change after adding NaC2H3O2 to it? Identify which ion is being added to the solution and how it affects the concentration of other ions present in the solution.
The pH increased. I am not sure about the ions. Na was added to the solution which increased the concentration.

Am I somewhat correct with these answers?? Could someone please explain? Thank you!!

Answer 1

A system of acetic acid will shift to the left if acetate ion is added to it; however, I don't think that tells you it is an endothermic reaction.

Answer 2

Well Na ions were added so would that still shift to the left? How do you know if it's endo or exothermic I have to include that in my answer?