Henderson Hasselbalch Equation Definition

What Is the Henderson Hasselbalch Equation in Chemistry?

Henderson Hasselbalch Equation Definition: an approximate equation that shows the relationship between the pH or pOH of a solution and the pKa or pKb and the ratio of the concentrations of the dissociated chemical species.

Examples: pH = pKa + log ([conjugate base]/[weak acid]) or pOH = pKa + log ([conjugate acid]/[weak base])