What happens when base and acid concentrations are equal?

When [A⁻] equals [HA], their ratio is 1, and log₁₀(1) = 0, so the buffer's pH exactly equals the acid's pKa — this is the point of maximum buffering capacity.

Does this equation work for any buffer system?

It works well for weak acid/conjugate base buffers within about ±1 pH unit of the pKa; outside that range the buffer's capacity to resist pH change weakens significantly.

Henderson-Hasselbalch Calculator

Calculate a buffer solution's pH using the Henderson-Hasselbalch equation, based on the acid's pKa and the ratio of conjugate base to weak acid concentration. Essential for buffer preparation in chemistry and biochemistry labs.

Inputs

Results

Buffer pH: 5.237

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Formula

pH = pKa + log₁₀([A⁻] / [HA])

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