How to use the Henderson-Hasselbalch equation to find concentration?

– Rearrange the equation to solve for the ratio [A⁻]/[HA]: [A⁻]/[HA] = 10^(pH – pKa). – If the concentration of either [A⁻] or [HA] is known, the other can be calculated using this ratio. – This allows for determination of the necessary concentrations to achieve a desired pH in a buffer solution.