Buffer Capacity and Buffer Index

The buffering ability of a solution is quantified by its buffer capacity. Van Slyke introduced the buffer index, $\beta = \dfrac{dB}{d(pH)}$, where $dB$ is the number of gram-equivalents of acid or base added to one litre of buffer solution and $d(pH)$ is the resulting change in pH -- i.e. the buffer index is the amount of strong acid or base (in gram-equivalents per litre) needed to change the buffer's pH by exactly one …