Inorganic and Applied Chemistry

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Inorganic and Applied Chemistry

We saw in the previous two examples how buffer systems damper external pH actions. In example 5-G the

initial concentration is 10 times lower than in example 5-H. This means that by addition of equivalent

amounts of H+ and OH-, the change in pH becomes different. The larger the initial concentration of the buffer

components are, the less pH will change by the addition of equivalent amounts of strong acid and strong base

respectively. In other words the buffer capacity of the solution increases with the concentration of the buffer

components.

5.5.1 Buffer capacity

The buffer capacity is defined on the basis of the amount of OH- and H 3 O+ ions that the solution may be able

to receive without causing a major change in pH. A buffer with a large buffer capacity contains large

concentrations of buffer components and may thereby be able to receive large amounts of OH- and H 3 O+ ions

without causing a significant change in pH. In general, pH in a buffer solution is determined by the

[A-]/[HA] relation and the buffer capacity are determined by the sizes of [A-] and [HA].

Acids and bases

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