Are there two Henderson-Hasselbalch equations?

There is a single Henderson-Hasselbalch equation, but it can be applied in two contexts: – For acidic buffers: pH = pKa + log10([A⁻]/[HA]), where [A⁻] is the conjugate base and [HA] is the weak acid. – For basic buffers: pOH = pKb + log10([BH⁺]/[B]), where [BH⁺] is the conjugate acid and [B] is the weak base. Alternatively, since pH + pOH = 14, the equation can be adapted accordingly.