The Henderson - Hasselbalch equation states that for a buffer solution which consists of a weak acid and its conjugate base, the buffer pH is given by:
pH
pkₐ is for the acid
In this case, the buffer hypochlorous acid HClO is a weak acid, and its conjugate base is the hypochlorite anion ClO⁻ is delivered to the solution via sodium hypochlorite NaClO
.