What does the Henderson-Hasselbalch equation tell us?

The equation provides insight into the buffering capacity of a solution and how it changes with the addition of acids or bases. It indicates that when [A⁻] = [HA], the pH equals the pKa, which is the point of maximum buffering capacity. It also shows how the pH shifts when the ratio deviates from 1, helping to predict the behavior of buffer systems under different conditions.