Adding a strong acid or base to a solution containing a weak acid or base, such as acetic acid, will affect the pH and equilibrium concentration of the weak acid or base. The extent of these changes depends on the amount and strength of the strong acid or base added.When a strong acid is added to a solution containing a weak acid, it will donate protons H+ to the solution, causing the pH to decrease. This increase in H+ concentration will shift the equilibrium of the weak acid dissociation reaction HA H+ + A- to the left, resulting in a decrease in the concentration of the conjugate base A- and an increase in the concentration of the weak acid HA .When a strong base is added to a solution containing a weak acid, it will accept protons H+ from the solution, causing the pH to increase. This decrease in H+ concentration will shift the equilibrium of the weak acid dissociation reaction to the right, resulting in an increase in the concentration of the conjugate base A- and a decrease in the concentration of the weak acid HA .To predict these changes using the equilibrium constant expression, we can use the acid dissociation constant Ka for the weak acid. The Ka expression for a weak acid is:Ka = [H+][A-]/[HA]When a strong acid is added, the [H+] increases, causing the equilibrium to shift to the left. This means that the [A-] decreases and the [HA] increases. Conversely, when a strong base is added, the [H+] decreases, causing the equilibrium to shift to the right. This means that the [A-] increases and the [HA] decreases.By using the Ka expression and the initial concentrations of the weak acid and its conjugate base, we can calculate the new equilibrium concentrations of the species after the addition of the strong acid or base. This can be done using an ICE Initial, Change, Equilibrium table and solving for the equilibrium concentrations. Once the new equilibrium concentrations are known, the pH can be calculated using the relationship:pH = -log10[H+]In summary, adding a strong acid or base to a solution containing a weak acid or base will affect the pH and equilibrium concentrations of the weak acid and its conjugate base. These changes can be predicted using the equilibrium constant expression and the acid dissociation constant Ka for the weak acid.