A buffer solution consisting of citric acid and citrate in a ratio of 5:1 maintains the pH at 7.4. What would be the ratio of the two components if the pH were to become 6.4

C: As the ratio of the two components changes, so does the pH of the

solution. As pH is a logarithmic scale, a pH value change by 1.0 requires a

change of one of the components by a factor of 10. This is achieved if the ratio

changes from 5 to 1, to 50 to 1. Furthermore, as the citric acid component has

been increased, the pH decreases to be more acidic.