The reaction between acetic acid CHCOOH and sodium acetate CHCOONa can be represented as follows:CHCOOH + Na + OH CHCOO + Na + HOThe equilibrium constant for this reaction can be expressed as:K = [CHCOO][HO] / [CHCOOH][OH]Now, let's consider the effect of changing the pH on the equilibrium position of this reaction.1. Increasing the pH more basic conditions :When the pH is increased, the concentration of OH ions in the solution increases. According to Le Chatelier's principle, the equilibrium will shift to counteract this change, which means the reaction will shift to the right towards the formation of CHCOO and HO . This will result in an increase in the concentration of CHCOO and a decrease in the concentration of CHCOOH.2. Decreasing the pH more acidic conditions :When the pH is decreased, the concentration of HO ions in the solution increases, which means the concentration of OH ions decreases. According to Le Chatelier's principle, the equilibrium will shift to counteract this change, which means the reaction will shift to the left towards the formation of CHCOOH . This will result in an increase in the concentration of CHCOOH and a decrease in the concentration of CHCOO.Now, let's perform some calculations to support these conclusions.Assume that initially, we have 1.0 mol/L of CHCOOH and 1.0 mol/L of CHCOONa in the solution. The initial concentration of OH ions can be calculated using the ion product of water Kw :Kw = [HO][OH] = 1.0 x 10If the pH is increased by 1 unit, the concentration of OH ions will increase by a factor of 10. So, the new concentration of OH ions will be:[OH] = 10 x [OH]Now, let's calculate the new equilibrium concentrations of CHCOOH and CHCOO using the equilibrium constant expression:K = [CHCOO][HO] / [CHCOOH][OH]Assuming that x moles of CHCOOH react with x moles of OH ions, the new concentrations at equilibrium will be:[CHCOOH] = 1.0 - x[CHCOO] = 1.0 + x[OH] = 10 x [OH] - xPlugging these values into the equilibrium constant expression and solving for x, we can determine the new equilibrium concentrations of CHCOOH and CHCOO. We will find that the concentration of CHCOO has increased, and the concentration of CHCOOH has decreased, as expected.A similar calculation can be performed for the case when the pH is decreased, and it will show that the concentration of CHCOOH increases, and the concentration of CHCOO decreases, as expected.In conclusion, changing the pH affects the equilibrium position of the reaction between acetic acid and sodium acetate. Increasing the pH shifts the equilibrium to the right, favoring the formation of CHCOO and HO, while decreasing the pH shifts the equilibrium to the left, favoring the formation of CHCOOH.