Which of the following is the overall reaction that takes place when a strong acid is added to a buffer containing equal amounts of acetic acid and acetate ions? A - HSC - SSCE Chemistry - Question 16 - 2024 - Paper 1

When a strong acid (H₃O⁺) is added to a buffer solution containing acetic acid (CH₃COOH) and acetate ions (CH₃COO⁻), the acetate ions will react with the hydronium ions. The acetate ions, which act as a weak base, will neutralize the added strong acid.

In this reaction, the acetate ion (CH₃COO⁻) accepts a proton from the hydronium ion to form acetic acid:

$ext{CH}_3 ext{COO}^- + ext{H}_3 ext{O}^+ → ext{CH}_3 ext{COOH} + ext{H}_2 ext{O}$

This demonstrates the buffering action of the solution, as the pH change is minimized when the buffer system reacts with the strong acid.