How do you answer a questions on how a buffer solution works?

This question would be a 5/6 mark question- marks are displayed throughout

You always start by defining what a buffer solution is: A buffer solution is a system that minimises a change in pH on the addition of a small amount of acid or a base. (1) Then you would write out the equilibrium of the buffer solution, for example, CH₃COOH (=) CH₃COO^- + H⁺ (2). The conjugate base in this solution is CH₃COO^- and the weak acid is the CH₃COOH.

Then you would explain the effect of adding a small amount of acid to the buffer solution:

The conjugate base (CH₃COO^-) removes the added acid. When an acid is added the [H⁺] increases and these H⁺ react with the conjugate base (3). The equilibrium shifts to the left (4), removing most of the H⁺ ions.

The weak acid (CH₃COOH) removes the added alkali. When an alkali is added the [OH^-] increases. The small amount of H⁺ present reacts with the OH^- to form H₂O (5). The weak acid dissociates, causing the equilibrium to shift to the right (6) to restore most of the H⁺ ions. 

I would the attach an example exam question which they can complete.