Answer:
The buffer system resists changes in pH by reacting with any added acid or base, which helps to maintain the pH of the solution within a specific range.
When a strong base such as NaOH is added to a buffer solution, the buffer system reacts with the base to produce a weaker base and a weak acid. For example, in the case of an acetic acid/sodium acetate buffer system, the reaction would be:
CH3COOH + NaOH → CH3COO- Na+ + H2O
In this reaction, the strong base NaOH reacts with the weak acid CH3COOH to produce the weaker base CH3COO- and water. This helps to neutralize the added base and prevents the pH of the solution from increasing significantly.
Similarly, when a strong acid is added to a buffer solution, the buffer system reacts with the acid to produce a weaker acid and a weak base. This helps to neutralize the added acid and prevents the pH of the solution from decreasing significantly.
Overall, the buffer system helps to maintain the pH of a solution within a specific range by reacting with any added acid or base and producing weaker acids or bases to resist changes in pH.