The dissociation of acetic acid CHCOOH in water can be represented by the following equilibrium reaction:CHCOOH aq + HO l CHCOO aq + HO aq In this reaction, acetic acid a weak acid donates a proton H to water, forming acetate ions CHCOO and hydronium ions HO . The equilibrium constant for this reaction is given by the expression:K_a = [CHCOO][HO] / [CHCOOH]Now, let's consider how the equilibrium position of this reaction changes with varying pH. Recall that pH is a measure of the concentration of HO or H ions in a solution, with lower pH values indicating more acidic solutions and higher pH values indicating more basic solutions.According to Le Chatelier's principle, if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust its equilibrium position to counteract the change. In the context of the dissociation of acetic acid, this means that if the pH of the solution changes, the equilibrium position will shift to either produce or consume HO ions in order to maintain the equilibrium.1. If the pH decreases more acidic conditions , the concentration of HO ions in the solution increases. According to Le Chatelier's principle, the equilibrium will shift to the left to counteract this increase in HO concentration. This means that more CHCOOH will be formed, and the concentrations of CHCOO and HO will decrease.2. If the pH increases more basic conditions , the concentration of HO ions in the solution decreases. According to Le Chatelier's principle, the equilibrium will shift to the right to counteract this decrease in HO concentration. This means that more CHCOO and HO will be formed, and the concentration of CHCOOH will decrease.In summary, the equilibrium position of the dissociation of acetic acid will shift in response to changes in pH according to Le Chatelier's principle. When the pH decreases more acidic conditions , the equilibrium will shift to the left, favoring the formation of CHCOOH. When the pH increases more basic conditions , the equilibrium will shift to the right, favoring the formation of CHCOO and HO ions.