Buffer Capacity Calculator

Calculate the buffer capacity (beta) of an acid-base buffer and the moles of acid or base it can absorb.

Frequently Asked Questions

What is buffer capacity?

Buffer capacity (beta) is the moles of strong acid or base required to change 1 liter of buffer by 1 pH unit. It quantifies how well a buffer resists pH change. Units are mol/(L·pH). A higher total buffer concentration C gives higher capacity. Maximum capacity occurs at pH = pKa, where beta_max = 0.576 x C.

Why does buffer capacity peak when pH equals pKa?

Buffer capacity depends on the product of the fraction of acid form and base form: beta = 2.303 x C x alpha x (1 - alpha). This product is maximized when alpha = 0.5 (equal amounts of acid and base), which occurs exactly at pH = pKa. Moving away from pKa in either direction depletes one form and reduces capacity.

What happens when a buffer is exhausted?

Once either the acid or base component is nearly consumed (typically when ratio exceeds 10:1), the pH changes sharply with any additional acid or base. This is seen as the steep inflection in a titration curve. Biologically, exhausted blood bicarbonate buffer leads to acidosis or alkalosis - the body compensates through respiratory rate changes.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.